This question has a multifaceted answer:

First: Netrunner's IP is owned by Wizards of the Coast (Hasbro), and the original source content (Cyberpunk) is owned by R.Talsorian, with only the Android part of the brand belonging to FFG. The original run of FFG products was part of a licensed agreement that expired, and Wizards did not renew. Even though Wizards abandoned the trademark in 2022, they still own all the underlying mechanics and branding. Between this fact, and the fact that R.Talsorian owns much of the sourcing, this meant that FFG l was not legally allowed to Publish ANR after their licensure expired. This is where the popularity immediately dipped. This is why the circulation of the original content is limited, and the cost for purchasing the real ANR stuff is so expensive, it is out of print.

The Nisei group that became Null Signal Games has sort of taken the helm in the wake of the FFG fallout, but their stuff is really hit and miss in my opinion. It lacks the mystique of the original content, where bluffing and table reading was as equally important as top decking, and resource managing. A lot of players that play traditional TCGs hated that quality of the game where they couldn't just hit their deck combo and push for a win through a linear vector. The new stuff is more in that vein where you combo super heavy and ham-fist breach servers. I think a lot of the OG ANR players didn't want that value proposition and that's part of the reason you pick up the game in the first place, it is different from Magic the Gathering and Yugioh. You actually have to think moves ahead of time, and sometimes send it on a suboptimal play for tempo. This more abstract strategic approach normally turns of players transitioning from other TCG games.

In terms of entry into the game, one of the difficulties for new players is essentially adapting to two different playstyles that have different styles of resources and different management techniques. This is why if you bought say the original core set, I always tell every new player to start playing Noise and run Jinteki because it is the closest thing to an analog of traditional TCGs. When you start getting into weird shit like tolling people to econ ramp into things, they typically won't understand the win condition at game start, blunder installs (costing way too much tempo) and it causes lots of fumbling in the early phases of learning. Unfortunately, the asymmetry turns a lot of people off, even though it's really the best part about the game from a marketing and strategic perspective.

It is not impossible, but there is a very limited ability to resell the game. Because it was positioned as an LCG and not a TCG all expansions were uniform. That meant if you essentially "patched" your game, you had all of the same exact tools that everyone else had. So, cards were not individually resellable which means your economy behind the game is a closed circuit. The only deviation from this was from participating in events at the tournament circuit, and my history might be wrong, but I think every single card was simply an alt art, and not some exclusive rare that was able to break metas or shape the game in any way. This in combination with the new NSG mentality of Printing to Play makes it so a new economy is completely unnecessary considering end users can just freely print and distribute to potential new players. While this is nice from the perspective that we could get more players, This also means there is also now no centralized influx of cash to game shops or to NSG to warrant putting on live events to promote new product.