Earlier quoted context omitted.
Hence roommates. $5500/month split 2 ways is $2250/month, which would still be ridiculous in any other city but is doable on a $130-140K base. Split 4 ways (that's doubling up in a bedroom) it's $1125/month, which is basically how non-tech-workers do it.
The author specifies living alone > $5,500 a month at market rate, which is affordable to a mid-level programmer at a large tech firm living alone I understand what you mean that roommates are the only way it could make any sense. But I'm trying to understand where the author is coming from.
You actually can pay for rent or food with stock at a public tech company; just sell it immediately upon vesting. Many mortgage brokers will consider it part of your income for the purposes of qualifying for a mortgage. For non-public late-stage companies, you can often get liquidity in secondary market sales; the banks don't like this and usually won't count it toward mortgages, but once it's cash it pays for rent the same as anything else.