Montreal doesn't have the greatest of economies. Reasonable standard of living, good culture, but Montreal is like Buenos Aires a little ... there is a weird kind of dysfunction and chill that doesn't exist elsewhere in North America.
Source: I live here.
Quebecois are not mean, but they are insular if you're not Quebecois or actually French. 'They eat at their own table in the cafetaria' kind of thing.
The economy is iffy and weak, and there's very few good jobs, even the good one's pay absurdly low.
If you're any good, you can move to the US and double your salary, which is why it's a kind of economic trap - young, good talent leaves and it's nary impossible to convince people to come even if the net standard of living is good.
You almost need a reason: like super choice job, spouse, contract job, family etc. etc..
Usually the places that are the 'most affordable' are so because the economy is not good.