He's basically Jordan in the 90s.
I know that parallel has been made ad nauseam, but it's the closest thing I can think of.
He's very good, no doubt, but there are 21 other positions on the team and coaches that are each very important to his success.
Marino was very good, but he did not have Montana's team and coaching to play with.
One of Mahomes' strengths is that he has ingested and internalized the knowledge and schemes that have been given to him and now has the ability to recognize what's happening on the field and execute the scheme, even while under significant pressure.
This along with a bunch of other players that know and execute their roles well, in the same schemes.
This doesn't just happen because of one man's individual talent.
The yankees have filled their roster with highly compensated top talent forever, but more often than not, they don't win championships.