This is not a capitalism versus socialism thing. This is a government versus individual thing. There will never be adequate capacity, because we will always be catching up to increases in population. The only way to solve the capacity problem is to give that capacity somewhere else to go. Right now, those who can afford to will go to the US.
But here's the thing. I live in Ottawa. There are, like, four hospitals I could go to if I needed surgery. Right now, under the current system, the government decides both if I need that surgery and how badly I need that surgery. The government gives absolutely 0 fucks if not having that surgery actually impacts me, and that would be true even if the system was properly funded. Me having only 75% mobility, for example, versus the 100% mobility I currently have, might be a low priority to the government but if it's preventing me from doing the things I need to do, it's a high priority for me. I do not have the ability, in Canada, to assert my priorities over the government's. The government says I can wait two years, then I can wait two years. If I lose my job, which then means I lose my apartment, which then means I move back in with my parents, which then means I no longer live in Ottawa, which then increases my costs of getting the care I need under this very same public system if and when the government decides to let me... that's my problem, not the government's. The government created that problem, but it's mine to solve. And my only solution right now is in the US. Solving it in Canada is illegal.
This is not a hypothetical thing. In fact, in 2008 or 2009, not only did this happen but the Republicans in the US beat Obama and the Democrats over the head with it when they wanted to bring in some kind of universal health care - look up Shona Holmes. She had a tumor that resulted in her going blind. It wasn't life threatening, so the Ontario government at the time said she could wait. Of course she exagerated the hell out of it (the tumor was not going to kill her, according to the Mayo Clinic), but it didn't need to. The government said she was a low priority, her life was impacted (going blind as an adult will do that), she could afford to solve the problem. Solving the problem is still illegal in Canada, so she solved it in the US. She should have been allowed to solve it in Canada, but government said no.
That is the problem, and no amount of funding the public system will solve that problem. If the government decides you're not deserving, then you're not deserving. Even if the government can afford it. Because here's the important part. The government isn't thinking about you. The government's thinking about society. And if society doesn't consider your problem a high priority, neither will the government. Just ask anyone on ODSP.