The inflation part is pretty key. $M2 has grown from about $7T to $18T, so if anything, housing prices
have tracked monetary inflation. It's just that the CPI has severely lagged monetary inflation, possibly because of cheap food prices, cheap oil, cheap microchips, and cheap goods from China.
There's a macroeconomic story for that: with roughly 80 million Millenials (in the U.S; ~3B worldwide) reaching homebuying age and competing for a housing stock that's not growing nearly as fast, the ability to buy a house moves up the income ladder, so that sellers can capture money from an increasingly wealthier homebuying population. Meanwhile, those ~3B worldwide Millenials are entering working age, driving the price of labor (and hence of anything built with labor, including food and manufactured goods) down. CPI of goods & non-professional services goes down, price of assets goes up.
This demographic trend reverses itself in about 10-15 years as the comparatively tiny Gen-Z reaches homebuying age, but in the meantime there'll be an even bigger pop as late Millenials (1990-1998) reach homebuying age and there are nowhere near enough homes for them all. I'd also expect inflation to start showing up in the CPI as Gen-Z starts to make up the new workforce entrants, boomers start dying off, and hence the labor force shrinks and wages go up.