Of all the biggest regrets SAF must have about his career...selling Stam, not signing Van Der Sar earlier, failing to lure Gascoigne, rejecting the opportunity to sign Zidane, losing those two CL finals against Barca...I'm sure his biggest regret of all is not picking Pogba against Blackburn. He must toss and turn at night, thinking to himself "If only....it would all have been so different"
His list of regrets seem to be endless it seems, but yeah, I agree with your post, because at the end of the day, Sir Alex has lost out on bigger fish than Pogba, and what did it really change? For me, it changed nothing. As for this argument about Januzaj, he must have done something to actually merit a place in the first team. I can remember, not having seen him play whatsoever, and to be honest, coming on against Sunderland in a crunch match that we clearly had to win, and I was thinking, ooops, Luke Chadwick all over again. In the end, his presence on the pitch that very evening changed the outcome of the match, and not because of the goals either. His will to win, his energy and his motivation help spur on the team, he was the kick up the arse that the other more experienced players needed and he provided it. People go on about how Pogba only had 20 minutes here, 20 minutes there, or other matches where he may have played 30 minutes or so, well, so what, it is what you do with the time that you have that counts the most. Again, with Januzaj coming on against Palace, he had only 32 minutes to try and impress the manager and he did just that, clearly doing more in 10 minutes than Young managed in 68 minutes. This was rewarded with a first debut against Sunderland and again, he provided something that I thought we'd never see for a long time and it inspired the others too.
So, all in all, whatever time Pogba had in the matches he played, destiny was in his hands, he had the chance to try and bring the best of himself and try and get a first-team place, but he chose not to it seems. However, if you have the ability and the motivation, chances are that a report will go back to Sir Alex and they will talk about the future, and the fact that Sir Alex let him go speaks volumes.