2. Patrick Mahomes has already won a Super Bowl and Josh Allen has not
Again, this could all change within a year, but for now, Mahomes is a Super Bowl champion, and Allen is not. Buffalo paid Allen the big bucks to hoist multiple Lombardi Trophies before exiting his prime, but keep in mind that he plays for a franchise that is notorious for losing four in a row. Jim Kelly was a hell of a quarterback, but going 0-for-4 in Super Bowls massively hurt his legacy.
Mahomes has already been to two, winning one in the final minutes and getting shellacked from the opening kickoff in the other. What this comes down to is the pressure being off Mahomes. He has one Super Bowl victory already, the same as NFL legends like Drew Brees, Brett Favre and Aaron Rodgers. Nobody can ever take that away from him. As for Allen, his career will be defined by one.
In short, the Chiefs can go out and play freely as long as this championship core remains somewhat intact. Chiefs Kingdom may covet another Super Bowl, but already having one in the ledger goes a long way. As for Buffalo, Bills Mafia has anointed Allen the next Kelly, only he is expected to do what their greatest quarterback in franchise history never could: Win a Super Bowl.
The longer Allen goes without winning a Super Bowl, the more pressure will be thrust upon him.