I sort of get what you're saying, but the Cowboys have had some pretty good teams during Dak's run....He had 4 years of a super bowl winning HC in Mccarthy. Up until 2023 the run defense really wasn't horrible and probably closer to league average than people realize with 2020 being a significant outlier season.
I tend to agree that QBs dont win or lose games on their own, but people really go out of their way to create excuses for Dak. Ultimately the Cowboys have not been able to even sniff a champtionship with him on the roster....Is that because he needs to play better? Maybe. Is that because the Cowboys front office just can't field a complete roster? Maybe. Either way it's fair to point out that building around Dak Prescott has not worked out for this team.