The reality is a bit more mixed. The fact is we don't really know what the best strategy is post-Tom Brady. Lots of teams have won with veteran quarterbacks picked up via free agency or trade, including two of the last three Super Bowl champions.
That said over the last ten Super Bowls seven were helmed by quarterbacks who were on the team that drafted them.
But then again Tom Brady accounts for three of those seven. A fifth round pick from the year 2000 doesn't really support or contradict the idea of basing your entire franchises hopes on highly drafted quarterbacks.
We don't know. I tend to be skeptical that its the panacea to all your problems, and when I look at the teams Joe Flacco or Russell Wilson won with I see overwhelmingly talented rosters.
No, we know.
It’s better to have a great quarterback than to not have a great quarterback.
The main way bad teams get great quarterbacks is through the draft, preferably as high as you can get.
Cincinnati would not have made the Super Bowl and 2 straight AFC title games without Joe Burrow.
Buffalo would not be a perpetual playoff team without Josh Allen, despite his recent struggles.
The Chiefs would not be the Chiefs without Patrick Mahomes.
The Packers would not have been a perpetual playoff team without Aaron Rodgers.
The Jaguars would not now be a playoff team without Trevor Lawrence.
The Colts would not have been a perpetual playoff team without Payton Manning and Andrew Luck.
No one is saying try to draft a great quarterback while ignoring the rest of the roster. We’re just saying it’s by far the most important thing. It’s incredibly obvious.