Building more high income housing still reduces housing costs at the low end. Every person who rents in a new development - even if it's $5000/month - is a person who isn't competing in a lower cost market.
Surelly there's a threshold which must be crossed before the highly paid pool is depleted enough to make such an impact.
Edit: To clarify, it's not as if tech companies, especially Google, are going to stop hiring and attracting more highly paid people to the area. 10,000 sounds like a number small enough to be gobbled up pretty quickly by SV tech growth.
Not that I'm in favor of turning the bay area into a high density population. A lot of what makes the region so nice to be, especially the peninsula, is the relatively low density. I really wish tech companies would make more of an effort to distribute their workforce and better leverage technology to enable remote work. It's really messing with the demographics, culture, and gender distribution of places like SV. When San Jose is being referred to as Man Jose, you've got a real problem.
I tend to agree, though it might be interesting to consider dynasmics in which this wouldn't hold.
Housing-as-asset-class, with phased new supply and demand stimulation might have opposite effects if the stock substitutes for other investment vehicles. Typical asset bubble.
