How much are you paying sites that aren't advertising supported right now?
How many more sites are you willing to pay at that same level?
Right now, as far as I can tell, advertising supported sites are out-competing sites that directly charge users, meaning that users prefer not to pay. That makes leaves advertising as the most sustainable model.
Some sites are involved in actual transactions that don't involve eyeballs and fractions of pennies these will be fine.
Simple sites designed to promote the spread of genuinely useful information can be designed to use microscopic resources and operate on little money these will be fine.
Some sites provide neat services people are willing to pay for these will be fine.
Some sites represent the online presence of organizations with significant budgets these will be fine.
Much of what remains isn't worth much and if no viable means of support can be found I guess they shouldn't exist.
Honestly 1/2 of the modern web could go away and not much would be lost.
It's only a crisis if your livelihood depends on making a bunch of crap nobody in their right mind would pay significant resources to support.
Google is an example of an ad-supported site that would be rather hard to replace. And, apparently, they make a ridiculous amount of money per user, so replacing advertising revenue with user payments is going to be expensive -- they'd have to charge you $277 per month, if you believe this:
That would imply that I am rendering $277 worth of value to Google each month. I would happily receive that in cash and eschew all Google services, which I mostly try and do anyway for privacy reasons. Where do I sign?
Well, the value you give google is the average probability of purchasing products.
I'm sure that if a large number of companies were able to cut $277 from your average aggregate monthly spending in exchange for a guarantee that you were buying their products, they'd be signing up. Perhaps some sort of subscription service that you couldn't opt out of. You can try doing that as a startup.
I would agree that Google search would be hard to replace, but I think it could be done, and probably done better. But one site is not worth keeping a crappy system in place, IMO.
A model out-competing another doesn't make it sustainable. Overfishing an area would make it out-compete another that doesn't, but that would be the exact opposite of sustainable.
How many more sites are you willing to pay at that same level?
Right now, as far as I can tell, advertising supported sites are out-competing sites that directly charge users, meaning that users prefer not to pay. That makes leaves advertising as the most sustainable model.