The truth is that there is no NHS system; NHS England does not run NHS dentistry. It contracts the job of running the show to those practices and corporates who have contracts. These get the blame if they fail to deliver a good service for patients.
Such 'outsourcing' is increasingly common in public services, with big companies like Serco, G4S and Capita leading the way. When it goes wrong, as it did with security at the London Olympic Games, it is the contractor, in that case G4S, that is blamed, not the commissioner, in that case London Organising Commitee of the Olympic and Paralympic Games (LOCOG).