There's no reason to believe it'll stop here.
Instagram was ad-free for quite some time. Now every third or fourth post is a big, unmissable ad. Same thing in stories.
Stopped using Instagram because even the "organic" posts are ads or product placement of some sort. It seems like every time someone hits 10k subs or more, their content becomes >50% ads.
Being unwilling to pay for a platform and simultaneously being unwilling to be shown any advertisements is unsustainable.
In the US, Facebook's revenue is $25 per user per quarter. That's $100 a year. Are you willing to pay the same or more than that just for access to their products?
YouTube Premium actually is a great example of how much that pricing ends up being: $11.99 a month.