We didn't have anyone outside of Chris Brown to play. You can't hand the ball off to air. Slaton was productive until injury. Salaam was the best option we had. Studdard didn't really hurt us ever, he just took up a roster spot. Okoye was held on to until it made sense financially to get rid of him. Jacoby had clear ability and still does. Richard Smith and Frank Bush were prompty fired after they proved they couldn't cut it. The coach plays the best players on his roster, it's the GM's job to upgrade that roster. Seems your issue is with the GM, which also doesn't make sense because we have upgraded literally every single one of those positions.
1) Nobody else to play...except for Arian Foster. I find it hard to believe that he didn't display enough talent and potential to be elevated to the active roster sooner than November 09, even harder to believe that he exhibited so little that Brown and Slaton were better options.
2) As a rookie in 2006, Winston would have been a better choice than Salaam who was mediocre on his good days and a liability on his bad days. If he were there to be a mentor, he could have done it from the sideline. Bringing him back on in 2009 to fill in during Brown's suspension was a major head scratcher when we could have given someone else some playing time. Classic case of Kubiak's loyalty problem. As for Studdard, I don't know what film you were watching but Studdard was a turnstile who couldn't run block to save his life - no way he should have been left in there for all 14 remaining games...he was also resigned in 2012 in another WTF moment, he has since been cut.
3) Okoye wasn't just on the roster, he was on the starting line. 11 sacks in 4 years. Benching him would have been fine to make it easier on the cap space, but Kubiak declined to do so. I think it's telling that he was gone the second Wade was hired as DC, 2+2 = Wade made that decision, not Kubiak.
4) Jones has clear ability...that didn't come out after 5 years and countless boneheaded mistakes as a Texan. It took blowing a winnable playoff game to finally get him out of here. He caught a TD pass in the SB, good for him. It doesn't change the fact that any other HC would have sent packing long before Kubes did.
5) Promptly fired after they proved they couldn't cut it? I'm pretty sure both of them were employed for an entire season. It was painfully clear that they were not NFL caliber (or even college caliber) mere weeks into their respective seasons. Bush especially, do you remember how dreadful 2010 was? A different HC doesn't hire them at all, most likely - another proof of Kubiak liking known quantities, though this is in a different sense.
6) I have mixed feeling about Rick Smith, he is a great talent scout and a bit lacking in contract management. Those being the two main functions of a GM, I don't see what he has to do with Kubiak's refusal to bench players who underperform, in some cases after several years of mediocre play.