AdTech just shows ads from the highest bidder. If a bicycle advertiser overpaid for ads and decided that they need millions of impressions, whereas a highly tar

AdTech just shows ads from the highest bidder. If a bicycle advertiser overpaid for ads and decided that they need millions of impressions, whereas a highly targeted toothpaste brand decided they need 1000 highly targeted impressions, you're going to see the bicycle ad first. Most advertisers just spray ads at people, so as a user, you end up seeing useless untargeted ads more than you see highly targeted ones.