I don't think it is that straightforward. Taking aside Mason, who I agree has been at this level for a long time without ever being trusted with big games, and Scott came into the PL very late, the "oldies" are very important. Atkinson, Marriner, Dean, and Moss are heavily relied on for big games, take them out and there is a real problem as it leaves just Taylor, Oliver, Kavanagh and Pawson for the big games, and possibly Tierney. All of those except Oliver and Kavanagh are in their 40s now, so not up and coming referees any more.
For me the bigger problem is the total lack of progression planning. Referees get promoted to SG1, but then don't get used except for a handful of games a season. Madley, Coote and Bankes fell foul of this, and whilst they are now getting games they are being used far less than the established referees (Coote is the most used of those this season with 12 games, but there are 11 more established referees with more games). The even newer referees, Jones and England, hardly get any games and spend most of their time either holding boards or in the Championship. They aren't going to get used to PL football like this, and need to be given regular runs of games.
And then the biggest problem of all is who is currently at SG2 with the immediate ability to get onto SG1? Gillett and Brooks potentially, Bond at a push, but there is no one really knocking on the door and demanding promotion. Other countries are getting referees onto FIFA in their late 20s or early 30s, I really am struggling to see England having any prospect of doing this. And of our FIFA referees, only two or three are consistently being trusted with top domestic games.