Most teams were set. They either had an entrenched starter or a young guy they still have faith in. Washington probably should have waited instead of going with Wentz but they didn't. That left the Panthers and Seahawks as possibilities. The next question was do those teams want to tank or take a shot. It isn't like this was a fantasy draft and everyone needed a QB. Dolphins think Tua can be the man, we'll see. Lions can't get out of the Goff contract. Giants are giving Jones a go and if some of these don't work out Mayfield is a free agent next year and they get a year to see him play healthy and make that decision.
Of course the 20 teams committed to their QB aren't interested in him as a starter. Mayfield wasn't interested ion being a backup.
Just because the Bills, Bengals, Chargers, Raiders, Chiefs, Cowboys etc... didn't go after doesn't mean that he is looked at as garbage, they already have a starter. There is only 1 starting QB per team.