maybe site-owners should pressure ad-providers to provide a track-free service ?
Of course you could argue the moral and inconvenience cases as sites make these judgements when choosing advert networks already but "a bit of tracking" does not have the same moral weight to most as "porn and gambling" or "the annoyance of pop-ups/unders and drive-by install attempts" when deciding where they are comfortable to take money from.
Without the latter the ads being compulsory is just enforcing advertising on your users without knowing if they even want it.
Also it is much easier (for a non-technical user at least) to just skip the ads on the web using browser plug-ins, than it is to get around them in an app, so to an extent this extra work may be wasted and the number of people who take up the "pay for no ads" option might not be enough to warrant the work that goes into maintaining it.
There are some sites that offer the "ads or pay" option so it presumably works out worthwhile for some sites, but I've not seen it often.