Flacco even now is a far superior qb, is far more accomplished, capable of throwing more than 15 yards, and for a team like the jags, broncos, or skins, who could be real contenders with a quality qb(yes the skins, they are a qb and a key player or 2 away from outplaying their organizations standards) they are certainly gonna want a qb who has actually proven something over a known hackjob, plus the fact that flacco will be a short term to see if he can spark some magic and if it fails the team can start over, tannehill will take a few more years commitment.
And on top of that, those are 4 possible suitors, and tannehill is one qb, and in a shit qb draft class there are still multiple suitors available