"FPTP has worked well for Canada for 150 years".

No, actually, it hasn't.

It ha led to some starkly undemocratic results.

The Progressives started campaigning to get rid of first-past-the-post before WWI.  Its failings have been known for a log, log time.  WLMK promised in 1921 to get rid of it.  But, being WLMK, he went back on his promise.