In my 20s, I was stunned to learn that my city's founding fathers got rich by developing land stolen from immigrant Japanese farmers. In my 30s, I learned about sunset laws, another large factor explaining segregation.

Growing up, it had been explained that racism was what other people did. Certainly not us.

Everyone's the hero of their own story.

Is the answer that the US left the gold standard and switched to completely fiat currency?

Or the US ended the trade embargo with China?

Or Walt Disney World opened in Florida?

There are several other general policy changes and trends that are far more relevant to housing.

With the passage of the Fair Housing Act, cities embarked upon thorough downzonings to prevent any new construction and "preserve neighborhood character" by not allowing more affordable forms of housing like townhomes and condos.

Prior to the downzonings, zoning capacity was very free, there's a great graph of LA's zoned capacity versus population over time, and it starts decreasing from many many multiples of population, and as population rises it falls to barely more than population. This sort of extremely tight constraint on housing, allowing it only in very certain areas, and in particular only if there is no small subset of homeowners that oppose it, is a huge change from the past.

You can also see similar evidence pretty much all over the Bay Area too. A six story apartment building in the Sunset may exist now, but could never be build now because of downzoning. You'll find lots of older duplexes in some parts of the Bay Area, similarly outlawed now.

This sort of planning trend wasn't limited to California by any means, and the Levittowns of suburban development embraced a development style of having nearly all land "built out," a state of regulation so that nobody with slightly less money could move in because apartments or duplexes were allowed.

We outlawed segregation so all those people who wanted it immediately realized they were wrong, racism disappeared, and we all lived Happily Ever After. Or that’s the way the Disney version goes anyway.

It was decimalisation all along!

That wasn't covered in any of my public school classes. Offhand, none of the teachers for history ever covered past WW-II. None of the material in the books (I read ahead) covered anything during the 70s or beyond either... though the district I grew up in did have some really old books for the time (over a decade old, and no dedicated class for 'recent' history).