That is and big if though. Yeah you, me and half the people here might leave over this, but we block ads already and so are not highly valued to YouTube or a lot of the creators and are only a small drop in the ocean of viewers.
YouTube is betting on more people turning off ad blockers then those that leave. And i am glad to see that it might be having a small effect on more people actually discovering ad blockers instead. Which I bet is something YouTube did not expect to see.