i would guess that being coldest country on earth, extremely high personal tax load, comically overpriced housing, declining quality of medical care, northern isolation, long & expensive travel to anywhere nice, weak economy, nanny state government, high cost of living, mediocre food and culture all have something to do with it. For digital nomads and skilled/educated young workers, there are better opportunities in dozens of countries. And for retirees, there aren't many worse places to retire than Canada.
You will be considered old for employment in Thailand even as a teacher. Not easy to come by. But Hua Hin is an older expat community and you will easily make lots of connections. Also a very low cost place to live, so work may not be critical with teachers pension from Canada. It's astounding how many Canadians are leaving that country. StatsCan says over 5 million living abroad