[vannevar]

I don't know the LA market, but there is a scenario where both supply and demand could remain constant and yet housing prices could still rise, and that's if the income of housing buyers rises. And if the income rises disproportionally, then buyers with relatively lower income can become displaced by higher income people buying additional homes to rent. Even though base demand remained the same, and supply in the sense of actual houses remained constant, a relative scarcity was created by the inequality in purchasing power between the wealthiest buyers and people lower on the income scale. And this can happen even if the lower income tier has actually increased its income over time, simply because it hasn't increased at the same rate as the wealthier segment.

[majormajor]

If I'm following, this scenario is basically "as the higher income/wealth people invest more of their money into more property, prices and rent can both continue to increase even if demand is fixed until the lower-income people are spending 100% of their disposable income on rent"?

Which is not entirely dissimilar to the general discussion around gentrification - those who can afford to pay more can displace those who can't - but a sort of special case that doesn't require migration.

Seems like there would be some sort of game theory aspect - this only works if something close to every landlord is pushing prices up?

I think what we're really seeing is more the high-migration "gentrification" case yet applied to populations that normally aren't who you think of as being the ones on the receiving end of gentrification: the 100M-dollar-buyers are pushing out the 10M-dollar-buyers are pushing out the 1M-dollar-buyers from California and then they go to Texas and push out the 500K-dollar-buyers... and it continues to flow out to touch everyone else too.