I'm shocked when people complain they can't make ends meet at a $400k income. A quick google search shows that the cost of living in San Francisco may be on the high side by American standards, but would be completely unremarkable here in Western Europe, where an income that high is almost unheard of. Maybe they expect too much? Do they want a large family villa with room for two cars and a 100 year old oak in the yard in a neighborhood that's not too, uhm, 'diverse', and no more than half an hour from work and the downtown area? Yeah, your bosses want that too, so that's why it's expensive. You'll have to settle for something less perfect, or move somewhere else.
The title on this question is a bit dramatic. After all, this couple does earn more than double Cupertino's median household income of $160k. The median home price in Cupertino is $1.74M so it seems like a better response than the whiny top response on Quora is: how can this couple <i>not</i> afford a home there on a $400k salary when clearly so many other people can?
I do pretty well for myself, money- and job-satisfaction wise. Yet I still stare at housing prices in Manhattan or San Fran or many other urban areas and wonder how there are <i>so many people</i> making <i>so much more money</i> than I do. What do they all do?!