I do not blame Osborne for hand picking his own successor and for choosing Solich. In hindsight, Solich did not work out of course, mainly because recruiting had fallen off under his watch, but that may not have been entirely his fault. Recruiting is an enterprise involving the entire staff and I think, from what I have read at least, that the staff was not recruiting as hard for Solich as they had in the past.
But why shouldn't Osborne have been allowed to pick his successor? In my opinion, he had earned that right and he had earned it in spades. After all, who the hell was Bill Byrne? Sure he was the AD but he was not the person who had brought NU football to the peak of the college football world. That was Osborne. And even if technically Byrne had the right to choose the next coach I am sure Osborne had in mind keeping the entire thing going as it had been going and sought continuity. And he probably feared that Byrne might hire somebody who would dismantle the whole thing and fire the whole staff with a new coach brought in.