Earlier quoted context omitted.
The point is taxes are second order. Locally (st.city) are based on either property values and incomes. (1) if incomes cannot support paying the housing costs, they cannot support higher taxes, because there is no excess earning power; (2) if people cant pay the rent, then they are likely to move away to "somewhere more affordable". Most people spend ~30 pc of their income on tax and another ~30pc income on housing.…
The funny thing is the counties where people weren't leaving (SF) had the highest housing prices.
- leavers are mainly people with established jobs, thinking of starting a family, who want more house per dollar (and more post-tax dollars per salary dollar)
- comers are mainly early 20s unattached aspiring professionals who aren't hit as hard by high real estate prices (price to rent ratios are still very high in SF), and who also don't yet have a large income against which to evaluate the tax impact
This kind of dynamic would result in a "perpetual churn" as each generation matures through their professional lifecycle, each time opening new jobs and housing opportunities (and thus the near-zero net migration).
Again, very speculative. But your observation made me scratch my head for a bit and this was the best explanation I could muster aside from "people just like SF and don't leave despite economic pressure".