I live quite far from NYC in White Plains, rent for 1 bedroom apartment here is $2400.
PS. I am sure there are people surviving for $500 a month in NYC, but that is not the lifestyle most developers desire when they have job offers for $80,000 to $120,000. In fact, most developers I've met say they want to make $10,000 per month to quit their job.
Jokes aside, I'm in a Crown Heights 1br for < $,1200
Assuming he has roommates, his rent and other fixed costs will be less than $1k, so he will be ok, if rather Bohemian.
You can even own a modest apartment on that salary: http://streeteasy.com/nyc/sale/789809-coop-3131-grand-concou...
Source: used to live/work there and just checked on craigslist.
If you can't survive on $3,000-$3,500 a month here, you have a spending problem, not an earning problem.
So that leaves around $1000 for everything else and any savings.. which means I think you are exaggerating when you say you live very well.
Tech job benefits certainly help keep expenses reasonable, too.