Hard to build a great team when the QB gets paid a monster contract. Russell Wilson was in year 2 on a cheap rookie contract. The Eagles won without a QB contract eating up their cap space. They had Foles playing elite on their run (and Wentz was in year 2 before he got paid). If you're going to pay a QB big money then you better hope he can be great enough to elevate the rest of the team and make up for other weaknesses (which is what Brady did and now Mahomes) and it's why they have multiple rings and worth every dollar. KC would have loved to have kept Tyreek Hill but with Mahomes, they couldn't afford Tyreek so they put their trust in their QB + a bunch of cheaper WR replacements. And Mahomes has found a way to make it work since they've made 2 straight Super Bowls.
Other teams that have paid their QBs are also facing the same issue...but at least Burrow, Allen, Lamar have taken their teams further than Dak has. Just because those QBs are falling short too doesn't justify Dak. Mahomes is going to break a lot of opposing QB's hearts...there's going to be a long line and Dak hasn't even been good enough to get in that line.