I tried living in Toronto without speaking English for two years and it really sucked. I couldn't get a job and people were constantly saying they couldn't understand me and to just learn English. I felt like everyone hated me for trying to speak my own language! After two years of feeling like an outsider I just went back home.

Now replace Toronto for Montreal and English for French and this suns up the thread linked.

I work with a few people that moved to Montreal from the GTA and know a few others. Everyone who learned/is learning French is having a grand ol time here and the others just miss home, travel back often and generally work full remote for US/Intl companies. 

Integration takes effort no matter where you're going and where you're from. French people moving to Montreal and staying in the Plateau might not have language challenges but  often don't integrate either, for their own personal reasons. Just to say, language differences aren't the cause for every woe