That the earlier you draft a franchise QB, the more likely the success?
I would argue that the rule is the more you prioritize the QB position, the more you support the QB position, and the more stability to have around your QB, the more likely the success.
Rams eating Goff's contract to get Stafford
Chiefs trading up for Mahomes when they had Alex Smith
The Ravens trading up for Lamar when they had Flacco
Bills trading up for Allen
The 49ers drafting 4 QBs over 8 seasons and trading for Jimmy G in one of those years as well.
The Cowboys drafting Dak Prescott when they had Tony Romo
The Eagles drafting Jalen Hurts despite having Carson Wentz.
These are some of the examples of teams who weren't willing to settle on QB mediocrity, and/or were aggressive in ensuring they had other QB options. If you also notice, most of these teams have decent offensive lines.