RTS games tend to be more skill based and thus less accessible for new players. For games that strive to have large audiences, it's important for games to have

RTS games tend to be more skill based and thus less accessible for new players. For games that strive to have large audiences, it's important for games to have a significant level of chance so that worse players can still sometimes win, the absence of this chance makes it so that new players will be losing most of their games for a significant amount of time until they become proficient. This is in contrast to DOTA or League of Legends, where a poor players will occasionally get carried by their team. I suspect that a compounding factor is that traditional base-building RTS games are hard to make work with microtransactions. RTS games tend to be very carefully balanced, and mechanisms to secure an advantage by paying would alienate any serious RTS player. This makes it so that cosmetic-only microtransactions are the only viable option. The reality is that microtransactions that confer advantages sell much better. Even games like Path of Exile and League of Legends that purport to not be pay-to-win do allow players to gain an advantage through paying (more rune pages for LoL, inventory tabs for PoE), but this would destroy a traditional base-building RTS. Company of Heroes 2 being a prime example, better commanders and hard-advantages being available for purchase was a deal breaker for many gamers. Who knows when the next patch will shift the meta and now you have to shell out another $15 to stay competitive. The reality is, RTS games never really were the stuff of AAA studios. Budgets for these titles reflected their more niche audience. Resounding successes like Warcraft 3 and Age of Empires were the exception rather than the norm. Publishers are aware that the addressable audience is limited, and so budgets are limited as a result. The RTS genre is still strong, but has become more the realm of indie and mid-market studies. The Total War series is the only one I'd really describe as AAA, and that's a mix of turn based and real time.