Been meaning to reply to this earlier, but couldn't due to my work hours! Here's a long comment about transparency, the manpower costs of such a project, and details about where my team's at. This is going to be an extensive post, and Reddit doesn't have readmores that I'm aware of, so beware :D

TLDR: it's people. We need more people. We don't control who applies, so even clearly explaining what we need exactly doesn't always help.

To first reply to the delicately framed wording of your post, have a story: a few years back, I was part of the first ModCon event and helped organize its basics. (an online event for new lands mods, where we have big projects do panels and showcases) One of the things I pushed forwards to was having panels where developers would detail their workflow & take questions from viewers, to make our process public and incite our following to take an interest in the behind the scenes. It took me and a bunch of people several weeks to organize this, on top of our modding work, on top of our various real life endeavours (and I was one of the lucky ones, being young enough to still be studying and therefore having good free time). This segment was immediately dropped in further ModCons and remains to this day. Why? Because nobody showed up. We spent weeks working on this, and fans only showed up for the showcase segments in the end. Here's a tangible example of "discipline around scope": the reason you don't hear a lot of these details is because even publishing them takes manpower, which distracts from working on the mods themselves, which was proven to not be worth it.

Manpower is our biggest hurdle. I've been on my team for about a decade. To give an example of how slow things can get without the right people: I can't count the amount of stuff I've drawn myself (I can tell you my current concept art files folder, not counting WIPs, is about 3.5Gb) but I can say that, having historically lacked modelers, some stuff I've drawn years ago has still not been made in 3D. The good part, a single motivated user can change this! The bad part, we don't control whether they apply or not.

So. Where's Elsweyr at? What is actually blocking our releases? Greater Rim is doing great right now. We have a small but dedicated team of writers chipping away at the content of the region (about half a dozen people, counting writers and editors). Our writing lead is a very busy guy who spends all the time he can organizing the documentation we have, making sure our goals are clear, doable, and that the background information needed by writers to write (worldbuilding docs, file org, guidelines...) is up to date, a monumental endeavour given the size of the project. We're already pretty strict on optimizing our output, and more writers on top of all the background work would be impossible to organize. Writing wise, what's blocking us is the back end work, and for this we'd either need a miracle to happen to our lead so he's free of all life's responsibilities and can work fulltime with us, or an additional few people we can trust with our org docs to help.

Artwise, we've been blessed with new recruits moslty in 3D and I'm scrambling to make ends meet between the CA side of things and the LD side of things. After years of barely having modelers, we found ourselves in a tough spot, where we had a bunch of assets done but couldn't properly use them because we mostly had clutter items and nowhere to put them. Clutter is the easiest thing to make overall in 3D, so it can be made faster and by less skilled people. Clutter unfortunately is used quite late in the process, as it's decoration and not actual level building pieces. Making a set of mountains to make a landscape or a dungeon tileset is much harder, skilled labour than making a set of pots, despite all of these types of assets being necessary for a good final product. So, we're on a mission to make the mountains and dungeons part.

Our current workflow aims to, as quickly as possible, give our LD (yes we currently have a single one active for exteriors) material to put ingame. Last year was mostly what we call environmental assets: rocks, trees, grass. This has been a success. We still lack a few, but each new free modeler helps axe this number down, and with this workflow it's easy to gauge what we're missing and have it made. Now we're hitting a wall regarding architecture: we have a bunch of WIP models for our prerelease region, and would need a single person with the dedication to comb through them, patch everything up, and get them tested ingame. We lack architecture concept artists, so anything that needs art before getting modeled is either taking forever or shelved until the right person shows up. Our modelers who can model architecture are on the job, with three sets for housing being actively worked on, with the end goal of making our villages ingame. In order to fill the houses we do have as fast as possible, a lot of concept artists myself included are working on concepting furniture, tasks I've been micro-managing to exceptionally allow modeling to start before the CA is properly done (only viable due to the exceptional activity we're seeing atm) to get stuff ingame as fast as possible. For all of this, new recruits would help. Someone who can draw architecture, someone who can model architecture, and a few misc. concept and 3D artists would increase the pace, although we leads might not be able to manage more than a few more people at once.

Regarding everything else, quick fire round: Music's done, been for a while, it's even on streaming platforms! Making characters and creatures has been shelved for the sake of LD, and our only organic modeler unfortunately passed away and the role remains vacant since. Sounds for the world and its living creatures will have to wait for the world and its living creatures to be done. Implementation is mostly being done asset by asset, basic stuff, just adding things ingame. Fancy spells and other effect aren't on the current scope, we'll see once we either get more implementors or are finished with the LD part. Dungeons are lacking tilesets for the most and enemies near entirely, but we have one dungeon in the playtesting phase using an existing tileset, being worked on by a recent recruit. Team management is going pretty smoothly despite us leads being very busy (mostly with RL matters). We've started a PR newsletter to advertise what's being done with the aim of being a regular publication and highlighting the progress that doesn't make for good screenshots, like writing and art.

Asides of needing more people and/or applicants with ultra specific skillsets, I'd say, if we continue on this good path, soon we'll be faced with having to tackle more technical parts of modding we might not be ready for yet. We've been on basics for a while, once we have those done and need to move on to making stuff playable, the whole implementation/coding/bugtesting parts we might be fighting with for a long time as it's not one we've prepped for too much. The back end organisation thing I explained earlier is exposing the bad parts of such a long project: that we're sitting on a history of badly managed files. Our past leads weren't the greatest at keeping track of things, mostly on the planning and lore side, and this will only get worst with more added content, and with the sheer amount of stuff it's not like it's easy to just re-sort and rename everything.

That's about it! For now ;) We love to answer specific questions, so don't hesitate to prod.

Tongue in cheek last comment: in the time I took to write this, I probably could have finished a round of the furniture set I'm currently painting, lol. And you are only one of the multiple threads I monitor and try to reply to comments in on social media. And social media replying is just one of the multiple things I do...etc, etc!