I'd be all for that. I don't mind paying for an increased user experience if I actually need it. This would kinda let the user opt out of the ad-based revenue model.
Unfortunately some people will try to hack it, tragedy of the commons and all that.
Sure, it may turn into an arms race, although one of the other points of adblock is also that it doesn't download the advert - so it's extremely easy to detect an adblock user.
I think if adblock usage increases (I don't think it will), we'd move to a 2 tier internet - a degraded slimmed down internet for adblock users, and the full internet for everyone else. Which I think would be fair and just.
This will not work. A good adblocker will load the ads, but it will not display them. This is basically what my recognition center did before I switched to adblock (and had an improved internet experience due to (massively) reduced load times and no annoying, blinking things). The important thing about the last sentence: You cannot assume I actually react to something in the ad, and the ads are loaded, thus, there is no way for the server to recognize a good adblocker.
Unfortunately some people will try to hack it, tragedy of the commons and all that.