It does not work like that.
QBs are expensive. So Elite QBs tend to go to the SB every 4-5th year.
But they tend to be top teams and in the playoffs for a decade.
Winning teams have great QBs.
It used to be the key thing that determined the success of a team was the quality of the coach. That was the #1 thing. Great coaches tended to win.
The rule changes have altered that. The key factor that determines the success of a team is now the QB.
Look at Denver and San Diego as perfect examples. San Diego isn't great. But they are going to be a playoff team shortly. Cincy already is, and did not really improve that much besides the QB play and the WR.
Meanwhile Denver is stacked. That defense was also legit. But the coach was still fired. Because they had no QB.
You get rid of Wilson, you get rid of your future unless you can find another great QB. (The good news, as others have pointed out, is that JS seems to have some sort of sixth sense for who is going to be a stud QB. So maybe slim chance we can find another - but long odds...)
Regardless, if you don't have a plan to get a great QB, you cannot let Wilson go. Because there is no playoff future without him.
Is going to the playoffs for another 5 years, and maybe making 1 more SB appearance worth it? Then you extend him (if possible).
Unless you just want to burn it all to the ground and start over. But you aren't running it back without him.