Canada also doesn't have 30-year mortgage terms. The loans are still amortized over 30 years, but you need to renew the mortgage every 5 years or so.
If you lock in a super low interest rate, you only lock it in for 5 years (10 years are available as well, but you pay a premium in terms of interest rate).
This sounds similar to the mortgage market in the UK. Longer term fixed rates exist but the rate reflects the yield curve over the fixed period (not just current spot rates) and there is usually a large redemption penalty. For example, if you sign up for a 4-year fixed rate deal, there might be a redemption penalty of 4% if you close it out in year 1, 3% in year 2 etc.
Canada has the pre-payment penalties as well. Wouldn't surprise me that origins of the Canadian system came from the UK.
The US typically doesn't have pre-payment penalties which is another benefit for US homeowners since if you get a mortgage rate of 6% and a 30 yr term and rates drop to 3%, you can simply refinance without pre-payment penalty and lock in a lower rate. You do need to pay mortgage fee with the refinance, but banks often have deals where the costs are pretty low.
That said, one has to wonder if the US mortgage rules create perverse incentives for US homebuyers.
If you lock in a super low interest rate, you only lock it in for 5 years (10 years are available as well, but you pay a premium in terms of interest rate).