Hip replacements

Paul Krugman has been another kick of writing about universal health care, and he write something today (Times Select) that is totally obvious but which I've never heard mentioned. Every time opponents or skeptics talk about universal health care systems in other countries they bring up the long wait times for specialty services. Krugman makes the oft-made observation that even insured people don't exactly have short wait times for specialty services (or really any kind of service... I had to reschedule a primary care appointment I had tomorrow, and the earliest I could book was August 13, and that's after major improvements in the student health center's personnel). But then he goes one to note:

"It’s true that Americans get hip replacements faster than Canadians. But there’s a funny thing about that example, which is used constantly as an argument for the superiority of private health insurance over a government-run system: the large majority of hip replacements in the United States are paid for by, um, Medicare.

"That’s right: the hip-replacement gap is actually a comparison of two government health insurance systems. American Medicare has shorter waits than Canadian Medicare (yes, that’s what they call their system) because it has more lavish funding — end of story. The alleged virtues of private insurance have nothing to do with it."

I mean, yeah! Duh! I've never once thought to make this argument, and I did research on joint replacements. But Krugman is right! Is there a reason to believe the wait would increase if Medicare were extended to the entire population? That wouldn't necessarily be the case.