Gee OP, I wonder.
>Easy to pick up and play (the most important factor)
>Viewers know exactly what's going on when looking at the screen, because of the above reason
>Runs on any toaster possible, so no one is left out from the starting line
>There's always something to do, like create a monument, reform a building or just random bullshit like a karma creeper to spice things up, so it's almost impossible to run out of content
>Easy to set up collabs to do the above reason
And then you have a RTS, where there is a lot of time investment to learn how to play and not get beat up in the campaign, the viewers who understand what's going on aren't sticking around to watch a chuuba messing up and gretting frustrated unless they are a huge fan, viewers who don't are just gonna get filtered out while including the above reason. This is all on a corporate vtuber environment, mind you, indies don't have to worry about filling a quota or permissions so they can afford to play it more often or not care about numbers.
Could be fun to see two players try to learn the game while fighting each other, like in an Age of Empires' Low ELO Legends stream, but that would be a gigantic debuff and I know the average viewer ain't gonna be down with that. At least when two noobs play a fighting game or another faster game, the rounds end quicker and cool flashy shit happens on screen.
In conclusion, your favorite corporate v-tuber will play Minecraft again this week, and you WILL like it!