You can't charge as much for that kind of ad, because it has poorer targeting, can't be updated as easily to facilitate shorter marketing campaigns, can't suppo

You can't charge as much for that kind of ad, because it has poorer targeting, can't be updated as easily to facilitate shorter marketing campaigns, can't support A/B testing, and probably a dozen other major things advertisers care about. I do occasionally see that kind of sponsorship, but only on websites that take very little time/money to maintain.