I don't know about common knowledge, but I actually share fairly similar speculation.
I think McNair looks towards the Rooney's as far as a model for a consistent blueprint for running a franchise, which means keeping an even level on things. For the most part I applaud this. However, I think McNair overly trusted Kubiak and I think he let Kubiak make the lion's share of decisions on personnel.
Let me state upfront: I don't think Gary Kubiak is a bad guy or necessarily a bad coach. I think the most consistent problem under Gary was identifying and developing talent. He seemed to gravitate to players much like himself as a player, not the most physically gifted but tried to make up for it in their approach to the game. He also liked to try to take long shot on some guys in fairly high spots; Molden as well as Okoye.
My other problem is that Gary did not seem to want people around he did not feel comfortable with or went out of his circle of what he knew. This lead to some really poor decisions on the staff in general. I think you can get away with this when you have a stronger GM who calls the shots in personnel and says: "I know what you're looking for in players, while I am not going to make the calls exclusively, at the end of the day this is what you've got to work with."
I am still not 100% sure that Rick Smith was allowed the ability to work anywhere near independent of Gary's decisions except maybe the last two years when it seemed the draft process (at least in my view) steered away from Gary making the calls. I am guessing this is why he likely still has a job.
I am relieved if nothing else some of the most questionable parts of the personnel side have been replaced, I still think there could be a few more specially if Rick Smith is shown the door next year if this team doesn't perform well.