This is a MYTH that must be ended someday. No, not only people living in most city centres are not rich, but they are even poorer than people living in the suburbs.
In my country, this the case for every single city except the capital.
I don't know Vancouver, but a 5 minute search of maps of densities and maps of income seem to confirm this again: centre, dense areas are the poorest.
And yet, on every thread (same in US forums or at my place) about transportation, transit, housing, bicycle(!), urbanisation, whatever that relates to cities, someone (or many) will come and say that people from the centre are rich and privileged and that the suburban people are poor and that they had no other choice than to move there to survive.
Truth is, except for a few slum-like suburbs, other suburbs are mostly populated by people who chose to move there to have a bit of a garden or to have bigger houses or to park their cars or to have dogs or to have a swimming pool, etc. and these people have a higher living standard.