That doesn't work well with AD networks though. Site owners will either have to use links of the form: siteOfAdNetwork.com?id=smthhere and it still will be possible to block them. Or AD network will be unable to check the number of clicks.
personalisation would be a problem, because you won't have a cookie, but there is always device fingerprint etc
I agree it isn't quite as good but it is possible to make ads indistinguishable from legitimate site content.
The only option I see here is to have some kind of click counter both on the web-master's (who monetizes) and client's (who advertises) web-sites. And the counters' numbers will be sent (using server-side) to the AD Network. But that doesn't work if the client wants to advertise not his/her web-side (where AD network's script can be installed) but Facebook profile or something like that.
Alternatively, AD network can charge not for number of clicks but for alternative parameters (e.g., number of days AD is published). Though, still not easy (no guarantees) to check whether web-master who's monetizing his/her web-site doesn't cheat.