Grassroots efforts everywhere, massive media pushes on the issue of privacy, monopolisation (still debatable imo) and ethics (Read: Amazon warehouse worker treatment), content creators shifting away from the ad model to donations (this could seriously damage YouTube in the long run), increasing use of adblockers, et al - these are just a few small things that really will set the wheels in motion against FAANG, though Apple and Microsoft are fairly safe because of their hardware business.

I don't think FAANG is going away anytime soon but the seeds are there. I'd rather these companies sort out their bad side than throw away all the work they've done.