As others have said, Twitch adblocking still works just fine. There are multiple plugins which block their ads, and you can even paste in a few custom filters to uBlock Origin and bypass them.
In other words, it's not inevitable.
Think of it this way: YouTube has to pay people to work on anti-adblocking tech, whereas pissed off nerds with a permanent "fuck you I do what I want" energy will figure out how to defeat those measures for free.