Paid for it, maintained it for 38 years, paid taxes on it for 38 years, paid interest on it for 30 years, paid insurance on it for 38 years, paid a realtor to sell it, made sure no junkies squatted it for 38 years, took the risk of the government force buying it for pennies on the dollar, took the risk of an earthquake destroying it, took the risk of other events completely devaluing it, didn't cash out for 38 years, etc.
Also took the risk of it decreasing in value relative to the dollar in 38 years.
I mean if it's free money, why don't you go buy up a $900K property and get some free money in 38 years? There is a little more to it, and of course, you realize, that it might not have increased in value over 38 years like it did the last 38 years.
Of course luck has a lot to do with it. I've lived in my house for about 15 years or so (not in CA). It's nearly doubled in value, but the interest payments alone over time cost about as much as the property, so it's a break even, then add inflation and I've probably lost some. I live in my house though, and I'm eagerly awaiting the day when I can live here without any more mortgage payments.