The core problem is that while people hold up that ads are the problem, the actual problem is that people like free stuff with no strings attached, i.e. have your cake (the content) and eat it too (nothing traded for it).
So when you present people an alternate way to compensate creators directly, they overwhelmingly just stick with ad blocking. There is a long case file of fools taking the internet at their word that "I want to give but the ads are so bad I can't!". They don't want to give lol
I agree with the caveats you outline, though. I think to work, something like this would need to be a box you'd tick when signing up for your ISP that promised some "ad free premium access to [X number] of sites" or similar, and you'd trade entirely on it being big name sites. Even then I'd expect relatively limited takeup mostly from people unaware of ad blockers.
How many people would sign up for a 15$ per month subscription to read one article with no ads? How many would pay 1¢ once to read the article with no ads? How many would sign up for one 15$ per month subscription to see no ads anywhere?
I realize we don't have the infrastructure to make high volume 1¢ payments, and probably not for lack of trying, but I just don't think the core problem is that people only want stuff for 0¢ and not almost 0¢.
I'm aware I'm preaching to the choir here on HN, but boy are there strings...
[1] https://proton.me/blog/what-is-your-data-worth-to-google
ISPs are already selling your data to a bunch of data brokers, I don't think ad spend is the only goal there.
In the old days, they'd run proxies, but with SSL, they no longer know where they are going, only that they are, for example, going to an AWS or GCP site.
That is basically the whole premise of the Brave browser though.