Currently, there are two ways to build a Super Bowl contender:
AFC way:
Be terrible and then draft a franchise QB that raises the entire level of the team: KC, Cincy, Buffalo, possibly Jax. Once the rookie deal is done, you going to have pay huge money to your QB which typically leaves roster holes.
NFC way:
Find a lesser QB or later round QB, then use your reduced financial commitment to the QB to fund a deep roster everywhere else: SF, Philly.
The NFL teams that suck are teams that heavily invested in the QB, but he is terrible; so, you have a flawed roster and a mediocre QB: Denver, Indy, Raiders, Green Bay (this year).