This just moves the problem down one level and doesn't change anything. If you're a host you only have an incentive to choose a trustworthy CA if by choosing a

This just moves the problem down one level and doesn't change anything. If you're a host you only have an incentive to choose a trustworthy CA if by choosing a lesser CA you're risking a significant problems for their users (who will switch hosts when they have a really bad experience and suddenly can't take credit cards anymore).