There of course were signs of decline last year. What did you see, though, that wasn't directly attributable to the thumb injury? Did his mobility decline? No, not much. His stats declined, as I said, and as would be expected with the team running more. Comparison to others? Manning played until 40. He had a clearly debilitating injury - which Rodgers does not. Favre played well into his 40s with some decline toward the end - all I can say there is he may not have taken as good care of his body as Rodgers. Marino I don't really remember, but I think there was some kind of injury factor there too. Brees, who you didn't mention, declined some, but he was at least serviceable until 42 or so. Brady may have declined some this season, but he's 45 or so, and prior to this year, he was damn near as good as ever.
Regarding receivers, I did say "lower quality and/or less experienced" - you know I have as high an opinion of Watson and Doubs as anybody, but they did lack experience, not to mention each missing major chunks of the season with injury.
Screwed up plays: there have always been those, and it's hard to tell whose fault they are - Rodgers, LaFleur, other players not executing, etc. In an overall bad season, those things stand out more long term, but they're hardly a sign of decline.
I've said, the O Line actually seemed better this year (better without the sacred cow than with him hahahaha). Part of the reason for less pressures, total numbers as well as the rate, was more use of the running game.
"I would love to see Rodgers throw 24-28 times a game for 280-320 yards and 2-3TDs" - what you'd love to see: That IMO is extremely doable going forward with a healthy Rodgers, even with the team relying as umch on the running game. I also thoroughly expect his interception rate - which rose all the way to almost as bad as most QBs - to drop back down to Rodgers-normal, which means practically zero.
CMI brought up QBs playing into their 40s, other than Brady: Obviously Favre and Brees just in recent years, and you could go back to Blanda, admittedly a bad example because he was primarily a kicker. It's a different NFL now with rule changes, better conditioning, etc. Most of the QBs who quit younger in recent times were never close to Rodgers or Brady level to begin with - literally nobody has been other than P. Manning.