All of those names are also individuals who've understood how things work in one particular scheme for a decade +. It's possible they don't know how things are going to piece together either and so their bias is a bit colored.
For instance, I gave the example in my PFF thread of how last year under Pete Carmichael the response to a 3rd and 13 would be to pass. That put pressure on Carr and the O-line to make something happen. Vs this year a 3rd and 13 is likely to be met with a draw play, or some sort of run that concedes the scenario, followed by a punt/play on field position.
One approach puts less pressure on the Oline and the QB
If you're more likey to pass on 3rd and 13 then you absolutely need guys who can pass block, and hopefully at a high level. However if you're going to run the ball in that scenario, that skillset gets minimized a bit through the game. Where you'd likely pass in that scenario 5 out of 6 times under Carmichael you may run in that scenario 3 out of 6 times under Kubiak. Therefore reducing the amount of times you need your O-line to hold up in protection.