this has happened before, they change things extensions stop working, new extensions are made.
as for chromium itself, what will most likely happen is a fork. brave etc already are forks, but kernal level forks exist too.
there are deeper ways to block ads than at the browser level anyway. os exists that do it, which will be the next move.
when you look at the tracking from win10/11 etc. blocking ads are only one part of the problem your os is constantly phoning home