The US weirdness of 30 year fixed-rate loans that the
customer can call at anytime and the bank can never call except for non-performance is substantially subsidized by the US Government.
Freddie Mac and Fannie Mae or whatever they are/were take those mortgages and basically convert them into government bonds that are then sold out.
Otherwise getting 2% for 30 years would be nearly impossible (and it IS impossible in many countries).
