I think some of this is a bit harsh. Honestly I don't think it matters who he sat behind. In Denver, he was likely already on some sort of "probation", but still managed to win the backup roster job (2018) after spending a year (2017) on IR. He also beat out Lynch who we forget was a 1st rounder... Not saying Lynch is all that, he's not, but still it's not nothing.
We can't say the coaches didn't think he was the best chance to win. We can probably assume that Denver (Elway is pretty controlling) was taking a calculated risk keeping him on the roster, and simply were treating him similar to the how the Colts did in 2019. The fact he won the back up job at all after the behavioral flags and a year on IR is something I wouldn't have bet on.
But I do agree he should not factor into draft plans. I think it's fair to say after Ballard's comments, he's still in the earning trust phase. Like you, I wanted to see him in the last couple of games, but I also knew that was unlikely as they probably didn't want to diss JB. Putting him out there, even in a situation where JB hypothetically got hurt, would have opened up a can of worms that likely couldn't be closed lol. In short, the FO played it ultra-conservative, and that does not surprise me one bit.
Whatever "plan" they have for him, I hope it's clear and finite. I got the opposite feeling listening to Ballard. It just felt like Ballard was saying, he needs to behave well, and if we ever need you, we'll let you know... I'd prefer a situation where it's clear as day, where Ballard says something like "kid, you've been a dumbxxx... you owe us two years of perfect behavior, XXX hours of service in the Indy community, substance abuse counselling, sports shrink counselling, and lots of hard work... and if you do that, you'll have a fair and open competition in year 3"... Kelly isn't in a position to complain about anything regardless of whatever conditions he's under, so who knows. I'd love to be a fly on the wall for some of those conversations though.