Actually-free gets suppressed by free-with-ads. We don’t know how much the truly free hobbyist-volunteer ecosystem would pick up without competition from ad-supported options (often with deep pockets for advertising and promotion, plus monopolist positioning to cross-promote with other products in some cases). Ad-supported options suppress usership of truly free options, which suppresses interest in volunteering time and resources.

It also suppresses open protocols. Protocols stagnated as the Internet centralized and commercialized for a reason. Some of these things could just be protocols.

Not saying that would cover everything, but I am sure those two factors would “step in” to replace some aspects of the ad-supported Internet, if the ads went away. How much, I don’t know.