it is a challenge, but its also that the past 10 superbowls mostly been won by a generational QB like Mahomes and the Goat. those don't fall off the tree. that's why they are generational and the Goat.
the only exceptions are Philadelphia who won it with a back up (beating the goat) and a definitely over the hill Manning and Stafford, who at some point may have been elite, but he was just a good QB when Rams won it. But away from these two QBs who tend to dominate, there was a mixed bag of how you win a superbowl, where Eli won it, Russell won it, etc. yes, at those times they played at a very high level.
one common factor in most of the teams is a great to elite defense for the year they won it.
with that said, about a 1/3 of the superbowl QBs are good QBs, not generational or Elite, ala Hurts, Grapolo, Goff, Foles, Newton, Ryan, old manning.
still they played at a high level the year they made it to the superbowl, so to your point high Level QB play is needed. and I agree, you can't go cheap, unless you built a fantastic team around them and have an elite type defense.