The poor Canadian citizen has his/her involvement by occupy and pay rent to the landlord.
Also, why didn't they buy in the right time instead of spending money, for example, on weeds?
Because:
(1) It's a matter of take it, or leave . If you don't agree to see place right away and sign the lease almost on the spot, the landlord can find at least 10 other people willing to. Besides, not many places in BC other than the Metro Vancouver area actually have any jobs.
(2) Most of the older generation (i.e. 35yo+) did. For millenials though, house prices have been at a very unaffordable level for a long time now.
To be clear, this doesn't pertain to me - I moved here willingly, and don't really have any right to complain about anything. I can definitely see the issue though for local people for whom Vancouver is part of their identity but who can barely even get by.
For example I know a French girl working for an "insurance company" in Mississauga. Compare to the common situation for many young people in France, I guess she earns a decent amount of money here. She is renting a bedroom close to Toronto downtown and commute by bus to work everyday. When I asked her why wouldn't she rent in Mississauga to lower her rent and save on commuting time/cost, she told be Mississauga would be too isolating for her.
You're correct about this not making sense and there indeed is a significant portion of people deciding to live in the most unaffordable of places just because (in Vancouver we have Kitsilano which is crazy expensive but huge groups of millenials live there). The older generation though (not referring to you) doesn't always realize that everywhere is expensive - I live in a suburb arguably in a less-desired neighbourhood but until a month ago I was still spending 40% of my take-home income (45K) on a 600sqft 1BR. No car, one-way 1h commute to work by bus. Many people I know would spend even more than that.
There's some more affordable cities in Canada (e.g. Edmonton, Calgary, Winnipeg) but most immigrants either are on an employer-specific work permit, or don't have an established network yet and for them the big cities are their best bet for a job. I think a lot of young people would take a job and live in a low-COL area if that was actually an option to them.