You're absolutely right, but this is a different case I think:
It's freerider problem, people WANT to use internet services, want to use social and so on, the problem is, if possible, they don't want to pay for it.
In the scenario where we make ads completely illegal, companies will look for other ways to monetize the service, because a system which is not in break even on the long term is cursed to bankruptcy.
People want to watch Netflix, but without paying, that means that if everyone do like that, Netflix will find other ways of monetization.
That's why games became full of microtransanction and always online stuff, for example.
That's what made ads popular in the first place, don't want to pay? No problem, here's a free sites with ads.
should socials be closed community where you can access only paying, like pay tv? Because even right now removing ads on Reddit or YouTube paying is possible.
Even Lemmy growth at a certain point will incur in this, because a platform can't hold itself on 2 unpaid developers and free labor of volunteers who pay for server costs too.
Would we better off without these sites if we're not willing to pay for them? Maybe yes.
But what certain is that without financial stability a project can't go far.
The problem is both of the producer of the producer, sure, but also its users should wonder how much they want the platform, because it will evolve accordingly.