From what I read on the internets, housing is also absurdly expensive in London, Lisbon, NYC, Toronto, Vancouver, Shanghai etc. Adjusting for the local level of salaries of course. So not sure what your point is?
A lot of this completely self-imposed (and very much by design) to prop-up real estate because there's no other industry to support the economy.
Vancouver is a prime example: it's extremely easy (compared to the US) for foreigners to purchase assets (even with questionable sources of incomes that wouldn't pass the higher scrutiny of USCIS) and for owners to collude into restricting the supply. They are happy since their investment appears to grow in value (they can get out of the game and cash-in if another foreigner decides to park his money into these assets) and the government is happy since a lot of people's retirements are tied to their home value and it gives the impression the economy is growing.