For the years that i was living in Ontario there were only 3 MRI machines across the entire province. The waiting period for that diagnostic MRI ranged from anywhere between 10 and 24 months. If doctors were even convinced you were worth getting it.

You could die from something before you could even end up getting properly diagnosed with it.

You might not have competent enough doctors in some countries for specialist treatment if you need it. A popular Canadian Youtuber who lives in Japan (which generally has great medical care) decided to relocate to the United States during the time they were undergoing their particular cancer treatment a couple of years ago. Japanese yakuza bosses pretty famously obtained their illegal organ transplants at UCLA Medical instead of in Japan...

The US's system is certainly flawed but it guarantees that you can obtain the best care possible if you can afford it. That's much better than not being able to get the care even if you can afford it.