There was a new AoE game but it’s struggling to compete with AoE2. It’s like trying to release a chess 2. People question why they would spend money to buy the new one when they still have the old one.
People are largely still completely satisfied with what they have now.
In sc21/2 your base starts 95% walled (and indestructible) with a choke that you can completely wall with about 3 buildings, but few would argue that makes sc21/2 boring.
In relation to RTS games, I think it's a combination of people are largely satisfied with what we have now combined with the fact that MOBAs, FPS, and RTS are probably more appealing to the average gamer.
Give it a chance before saying such fatalistic statements. Play some lesser known ones. I mean this is a site that found it's roots in startups, and they're are all about being the upstart and being the hope for something better.
There could always be a sc3 or aoe18 (or whatever). There are infinite areas to explore.