Yes, you could make $6000 CAD a month, but your 900 square foot flat will cost you $3000 of it to rent. If you are currently living in Winnipeg, Montreal or Vancouver, your grocery bill will be double what you're spending now when you get to Hong Kong. If you're in Yellowknife, a third more. Further out, maybe about the same. Gym membership in HK is double the cost of Canada. Children's education comes partially out of your pocket every month and sports, dance or music lessons for your kids are double (or more) the cost in Canada as well. I've been at CX almost 10 years and no prospects of a Canadian base in the foreseeable future. London maybe, but not guaranteed. Ability to commute from HK and super compact rosters is a player as a SO, but as a FO would depend on what fleet you're on, which you have no control or say in. Airbus, not a prayer! 747 is now just a freighter fleet, probably not until about my seniority. 777 would have a good shot, but almost everybody in the company senior to you is trying to get on the 777.
To put it in perspective, an acquaintance (777 FO) just quit CX to join Encore. They see more future there than here. Feel free to PM me if I can help or you want more details.