This is a real problem in Canada with the chargers. Petro Canada advertises 350kW stations but from what I have seen on plugshare, all the ones I have seen so far are throttled to 50kW.

Whoa...
Let's not make an assumption over 3.8 million square miles over localized experiences.
My experiences in Alberta (Canada) last month:
PetroCanada Canmore, Alberta:
180 kW
Electrify Canada, Canmore, Alberta: 120 kW (on a 150 charger) 145 kW (350kW charger) - no pre-conditioning.
Shell Calgary, Alberta Airport:
180kW
Red Deer Electrify Canada (twice):
367 kW, 338 kW
Tesla? U/K... still no NACS adapter despite ordering Sept 27