The flexibility is in what you buy. Rent is flexible in the sense that you can choose what to rent, and whether you have people paying with you (roommates). And so on with other expenses; a new Tesla or a 8-year-old used sedan? etc.

SV's problem is that even the minimum rent is pretty high, but that's a local problem, not a universal.

Everything in that list involves choice: where you want to live is a choice. (based on family size, crime rates, school quality, access to transportation, whether you have pets, etc, but still a choice) Even the things that have static prices involve consumption choices (ie, how much gas you consume)