Maybe I'm just underrating Edelman, but I think he more than any other skill player in the Brady era was helped by playing with Tom. He was undoubtedly more versatile than anyone in the current group (and it's unlikely anyone on the roster gets a chance to equal his postseason accomplishments) due to his ability to play defense and special teams, but purely as a receiver, I just don't think he was materially better than what guys like Parker/Bourne/Juju (I'm bullish on the latter regaining some of his form, he wouldn't be the first free agent to struggle early) can do. It's somewhat of a shame that we never got to see him play very much without Brady, but I suspect if he'd left the Pats, he would've vanished pretty quickly. I also think he benefited greatly from playing with Gronk, who just opened up everything.
Fair point on White, although Stevenson caught 69 passes last year, which is right in line with what White averaged from 2015-2019 (63 per year, 71 per 17 games).
I agree 100% with KFP that after Brady, the difference is the O-line. I won't try to parse whether it's coaching, health, chemistry, personnel or simple execution, but no one (not even Brady) could make the offense look good when the line is this bad.