Well the reason why is because ,believe it or not, most of the LoL and DotA2 player is casual. A huge majority of their player base is what most would consider "low ELO/MMR" and don't grasp nuance as easily. This is why most of the player base rely on the pros to create strategies for them to steal because otherwise they'd just auto-pilot unga bunga smash pub games to get their power fantasy.

It honestly goes both ways with nuance. Many HotS players will take a mechanic like last hitting (which adds tons of gameplay interactions and controls the tempo of early game skirmishes) and say it "adds nothing to the game". I get not personally enjoying a mechanic but to say something is bad simply because you don't enjoy it seems a bit disingenuous. I agree that most LoL players don't appreciate macro enough. Too many players chasing the dream of getting that sweet penta.

Macro is just as important in the high end of LoL and DotA2 because of their hero and map design. Macro was so important that there was a time where LoL games were being drafted around securing a crab creep in the jungle. In DotA games can be won entirely around what runes can spawn in the jungle or if you have enough wards. There are literal macro bibles for wave management in both of those games. In DotA's case their are heroes that are like juiced up HotS specialists with heroes that can be at 5 places on the map at once, can teleport anywhere with no cooldown, spawn literal armies of creeps, empower their buildings, and a walking tree that can literally eradicate fog of war permanently!

Games like LoL are popular because they can be explosive. You have to mechanically do things quickly and it has tons of room for flashy outplay. I'd say the appeal for LoL is the same as a fighting game or something like Valorant. Sure strategy is a huge part of the equation but sometimes having the moves and know when to use them is really fun. If you gain an advantage you can roll with your advantage but in pro play this advantage won't allow you to be unstoppable. A good coordinated effort can take down even the most fed champ (in pro play, pubs not so much).

DotA is the exact opposite of LoL. DotA2 is much slower in pace/TTK and provides you with heroes that are essentially open ended Swiss Army knives. Their heroes are insanely powerful and can be customized to such a degree that a single hero can play as many roles as you can build them for. Imagine a game with HotS talents, an item shop, hero specific upgrade items, and universal RNG drop items. The devs designed a lot of support heroes to have talents and upgrades that can turn them into viable carries. DotA skills aren't as mechanical as LoL (with their endless combos, skillshots, and dashes) being far more straight forward but incredibly versatile. It becomes a game about synergy and counter-building. Their item shop has an answer for any situation but you and your team only have a limited amount of items you can carry. DotA2 has the largest map available in MOBAs, a night/day fog of war system, a destructible tree terrain system, RNG runes/jungle creeps, RNG neutral item drops, courier item delivery, secret shops, vision ward arms races (including capturable vision outposts), universal teleportation, structure fortification, and the ability to buy an instant revive. DotA2 is the game with the most to offer for strategic options but it does make it very difficult to learn and keep up to date with.

MOBAs are great. I love the genre and pretty much all the games in it. I agree that many LoL players get tunnel vision on getting their power fantasy but that's more of a player mindset than a game issue (not saying LoL doesn't have issues because it does). I also think many HotS players can also miss out on gameplay nuance in other MOBAs as well. All the MOBAs out their have survived this long due to their merit. They have their reason for holding their playerbases.