I'm not fully sure about this, an ad network which does that very reliably can probably charge the ad provisioning companies extra due to it being on more high quality sides/locations and pay out extra little due to having "high quality low disturbing" ads.
But with the Google being a quasi monopoly for ad networks on any open platform and most people either blocking all adds or no adds there is just little room for alternatives. I do use uBlock Origin for some custom filters, but I which instead of "on" / "of" there where "on but more like privacy badger" / "on full" / "off" with the first being the default so that users can create an insensitive for better ad handling.