It largely draws from people that in an earlier era would have played RTS, with macro management and build orders removed. It also has a lower barrier to entry. Trying to get into competitive AoE2 nowadays requires you to remember not just unit matchups but 20 years of civilizations, their bonuses and unique units. Which is a bit more effort than firing up DotA and learning the relatively fewer units.

I use to play LoL, and had a great time, but you know, you can only do the exact same thing on repeat on the same map 100 billion times, so after a while it was time to move on with my life. I did play some of the others, but they were basically exactly the same, but weirdly enough every dude, freind and rando alike, who still plays them a decade later gets all if I don't want to play dota. It's so fucking annoying.