Today's web is the opposite of what early Internet utopians had in mind. Now the situation is somewhat similar to climate change: even committed activists can no longer turn the tide for the better.
As far a I know the porn industry has actualy driven innovation in various web-technologies including streaming, e-commerce, VR...and now probably AI, I guess.
I don't think the biggest part of the internet is porn. There's a LOT of porn and a few really big porn sites, but I don't think they hold a candle to social media and shopping.
I found this link that has porn being #s 14 and 15. It was actually hard to find recent data that included porn at all. I think some counters were too embarrassed to admit porn existed.
Those are just the biggest sites. Also 12 is a porn site. But it doesn't say anything about the size of the total porn on the web. Like, amount of sites and content. Estimates are roughly 80% of the entire internet is porn.