And little or no job security or career mobility.

Really depends on your lifestyle, don't you think? Plenty of people are happy with a 1 bedroom if it lets them live in the heart of a city they love. Different people have different priorities.

Living conditions have a large impact on productivity and general mental wellbeing. For introverts, I think there's an argument to be made that splurging a bit on more space for yourself could lead to better performance in many areas of life. It's hard to put a dollar figure on that. For extroverts, this may be less true.

I feel like I should point out that in most of the country, including large cities, it's hard to even spend $2k/month on any apartment, let alone save that much by opting to have roommates.

> It's just one of the least productive things you can do if trying to save money.

... in SF.

In most other cities with many tech employers, NYC excepted, living with roommates instead of in a 1BR isn't going to save you $2k/mo. Median 1BR in Austin or Seattle is less than $2k/mo. Yes, housing is still your biggest cost, but it's so much cheaper than SF, and the taxes are lower than California. The marginal savings you can get by reducing your standard of living aren't as huge as in SF.

For the same price you could live in a nicer whole apartment, in most of america. I pay $1200/month for 1664 sqft in a nice townhome, with a garage, next to a park, as a software developer with plenty of opportunities and no I'm not going to tell you where I live or else you'll all move here lol.