I didn't say the QB was deemed worthy though. Mediocre-to-average QBs get crazy deals. Teams hate giving up even average QBs, so they overpay by 20-40% just so they don't lose them.
Also remember that paying someone 50M doesn't mean they will have even one good season on their new contract. The team is on the hook no matter what, but the player is not required to actually live up to the deal.
Wasting one of the top picks in the draft so you can drastically overpay after 1 or 2 *decent* seasons is the kind of move that teams at the bottom make.