The thing to do is compare the stall/spin rates of the US (which does not require spin familiarization) and Canada (which does).
My understanding is that the rates are almost identical.
The problem is not that US pilots don't know how to get out of spins. The problem is that both US and Canadian pilots are getting into spins too low for recovery. My own case is a classic example; it happened at ~2,000 AGL, but it was a maneuver I had been doing in the traffic pattern. You'll find few cases of planes spinning down from altitude. So the FAA emphasizes stall recognition and recovery, instead. Avoid the stall, avoid the spin.
Yes, there are some cases where the Canadian pilots' training have allowed faster recovery from spins. It's supposedly offset by a higher rate of accidents during spin *training*. This was part of the justification when the FAA eliminated spin training from the Private syllabus.
Ron Wanttaja