@spazahedron Because they can't track you they can't try to sell you six more lawn mowers to go with the one you bought yesterday, so they'll show you random stuff instead.
The ads are only "lower quality" insofar as the ad exchangers can't charge advertisers as much money for untargeted ad slots.
In other words, "lower quality ads" is a self-own by the bloated leeches degrading your browsing experience.