There was a bit in that interview he did a bit with Rio Ferdinand where when asked about playing fullbacks he made very clear he was a CB and was only doing a job for the team and wanted to play as a CB. It didn't sound to me he was enormously happy with the role he had.
He must also see that there is a lot of speculation about a new right back. There was probably a world, where Ancelotti and the club essentially knuckled down with Holgate and decided he was the medium term choice and would get a run at it, and given time to improve. Whatever the rights and wrongs of that (and I appreciate it's probably an unpopular view that he could be a 1st choice) it has been decided that is not the avenue they are going down.
I also have a theory on this utility player stuff, that is essentially since more subs came in, it killed the utility man. Even till the early 00's you were only allowed 3 subs, so a lad like Holgate either on your bench or on the pitch gave you options of changing shape or playing a number of players. There was a value in them. The movement to 5, then 7 now 9 subs has essentially killed that off. I don't think it's the key element by any stretch, but versatility is not as key a component as maybe it once was.
As I've got older I've become more ruthless about such things as player trading. I like Holgate, but if theres a choice between a 4th choice or 15-20m pounds my answer is clear. That doesn't mean I don't like Holgate at all, but the money can be better spent. It's like saying would you rather Hoglgate or a 1st choice rightback akin to Lucas Digne? It's not a zero sum game.