On a related point, I visited Sunnyvale from the UK last week and was surprised to see legions of battered RVs parked on the backstreets in the area. What's going on there? Is it workers who can't afford to rent in the area?

Read the news articles on the subject. There's a vast number of gainfully-employed people whom don't wish to fritter their relatively meager earnings away on techie-inflated rent. Most people in the area cannot legitimately afford to live there as they would be spending more than a sensible amount on housing because they can't ever hope to earn enough to be considered middle-class. Still, the area needs janitors, cooks, teachers, bus drivers, human resources and more non-techies whom rarely make much in a normal American city. Instead, they make some sacrifices to keep more of what they earn and opt-out of following the other lemming off the cliff into perpetual debt peonage.

Yes. And many of these people work at some of the biggest companies like Google, Facebook, Apple, and other tech companies. And, it's not just the support labor for janitorial, kitchen staff, etc. Many of these RVs are used by entry level and new in career salary employees. Unless you have a dual income family making very solid pay or have a director-level plus salary in a home, it is often not possible to own or at times even rent a home.

I’ve lived in Sunnyvale for six years now and one thing I’ve noticed is that a lot of the rv/mobile home parks have shut down and been turned into luxury apartments.

Surely raising taxes and throwing more money at it will solve the problem!