I'm imagining the constant shit show that would be the inboxes of the responsible Premier League, FA and PGMOL staff and whether they could ever care about how long throw-ins are taking … imagine you're a young firebrand trying to reform this stuff at PGMOL, then you realise you're about to be called into a Zoom with your line manager with Howard Webb dialling in from Coney Island.
If I were to guess at a reason none of this stuff seems to get any better, I reckon the strained corporate structure in which the Premier League is part of the Football Association for the purpose of the Rules, but isn't run by the FA except for certain veto powers over its executive appointments, and Professional Game Match Officials Limited is yet another independent company co-owned by the FA, Premier League and Football League, that cluster's gotta play a part.
Not up on the history, but I assume it's like this to ring-fence more of the filthy lucre from the top flight.