Huh?
Team defensive rankings over Herbert's four year career in points allowed: 22nd, 29th, 20th and 26th this season. His offensive lines have been a joke, bottom half of the league in rushing and a rotation of nobodies. And who were his amazing weapons? Keenan Allen was almost 30 when Herbert entered the league as a rookie, Mike Williams has played 14 games once during that time and he's almost 30. Oh yeah, then there's that problem of Herbert being coached by morons his entire pro career.... he's on his third head coach in four years.
Mahomes is not a unique in that he's surrounded by offensive talent, starting with one of the most expensive offensive lines in the NFL. He also has the premier offensive coordinator in the entire NFL in Andy Reid. His first year as a starter his defense stunk and they lost in the AFC Championship game. Reid immediately fired the defensive coordinator and hired Steve Spags and won a ring the very next season.
We saw Burrow explode out of the gate, but he had a bad offensive line so he sustained a knee in jury his rookie year. Then Burrow with great weapons and a horrible offensive line led the team all the way to a Super Bowl, where he subsequently got sacked 7 times and lost the game. The following year he and his super weapons got to the conference championship game, where he subsequntly got sacked 5 times and lost the game. Now Burrow is injured and can't play. He and his super weapons sustained it as long as they could... you don't just need the QB, you need the line, the weapons, the defense, the special teams and the coaching... you need it all.
With a great QB the last three years instead of Mac the outcome for this team is completely different. If they're battling for an AFC title Trent Brown doesn't opt out because his team only has two wins, Rhamondre probably hasn't shut it down for the year.
The line has Onwenu, Andrews, Strange, Sow... they need a left tackle next season assuming they re-sign Onwenu. They had great TE's, great RB's, and may have only had #2's at WR but so does 3/4's of the NFL. The defense is a top five unit despite carrying the league worst offense behind them and missing the single best player on the entire team in Judon and its two best young CB's.
No talent?
They need a QB, a kicker, a LT and to re-sign their own free agents... but it starts with finding a capable QB. They have a nice base of talent and the most cap space in the league going forward. Find a QB... the rest is easy.