I think Glennon being so atrocious caused the coaches to play Trubisky before he was ready, and I think that's a large part of the reason for both his play and presence in the pocket, and the limitations in the game plan. Watson was more NFL ready, obviously, and would not have had these issues to the same degree, if at all.
You say you think Watson would likely be doing worse than Mitch is if he were here. Does that mean you think Trubisky would be doing better in Houston than Watson's record breaking performance and he would be the best rookie QB in the last decade? If you do, I can't help you, because you're just too deep in the homerism to be rational.
Regardless of what you think about accuracy or radar guns, Watson is better than Trubisky on the field because he's a more naturally capable playmaker than Mitch is. His instincts are off the charts. The assertion by you and others that all of Watson's success has been about his teammates carrying him and all of Trubisky's mediocrity has been about his teammates letting him down, and that neither of them are individually responsible for any of it, is just nonsense. I can guarantee you that if Trubisky were having the MVP-level rookie season and Watson was struggling, you would say the opposite.
This insistence by some posters that every issue with Mitch is to do with the receivers, game plan, coaches and everything else other than him, is beginning to have a rather familiar ring to it.