Earlier quoted context omitted.
Culture, and the reputation it earns. I’m no amazon apologist, but one thing I trust them to do is keep my things running as they are.
In a world where there are three players, culture and reputation are not worth much, if not only at the beginning. Maybe 5/10/15 years from now the software and competencies to manage bare metal will be only behind the doors of those three companies, and at that point it will be economically convenient for them to act as a cartel and increase prices.
Ubuntu is actually heavily investing into MAAS (metal as a service) and so is Redhat with cobbler and foreman. So I'm guessing there's enough demand to justify their development (as every major cloud provider uses in house tools AFAIK)