Kind of makes sense to me, once you get to a point where you're set. That is you can easily afford the main things (housing, food), plus the extras (electronics, vacations, hobbies) you need a much larger income to "move the needle" so to speak. You still need to work 40 hours a week or whatever, and only get X weeks of vacation. Having a 180K salary instead of 150K doesn't change any of these obligations, or change…
I live in the Netherlands where 40K is quite a reasonable income. I really dont get why you would need 100k to do the things you need. Perhaps people need to become a bit more frugal?
People here in general don't have any debt (except for mortgages) and a vacation to an Asian country is 1-2k/month'(yes people sometimes do take 2 months vacations here). Even a month of Australia is only 3-4k. Hobbies? I don't know what kind of exotic hobbies people have in the bay area but even flying drones (relative expensive) is relative affordable if you get started with a cheap Chinese drone before you buy an Expensive one.
Rent, family size, location, etc probably makes a huge difference but I really don't think 100k is the magical number that you need to become happy.