Also a Canadian living in the US, and I would tend to disagree. In major US cities, with good health insurance, there are plenty of PCPs, and availability of specialists.
For instance, I had a ganglion cyst that I went to see my PCP for. We decided to give it a couple weeks to see if it would go away by itself. It didn’t, so I messaged him, and was scheduled to see an orthopedic surgeon (probably overkill) within 3 days to have it looked at and drained. Total cost: $0 for PCP; $40 co-pay for the specialist.
Meanwhile, my father in Nova Scotia waited close to a year for a knee replacement surgeon consult and is now waiting for surgery slot, which is expected to be another 6-9 months, despite being in significant pain. That just would not happen in the US.
There are many problems for sure, and I don’t have a universal measure for efficiency, but anecdotally, in my experience, there is just way less waiting in many parts of the US. I also acknowledge how privileged I am to have good insurance, resources to not worry about large out of pocket maxes in an emergency, and to live in a city with some of the best hospital networks in the country.