Why does it matter though? The absolute number without taking cost-of-living into account doesn't really mean anything.
First, if I'm looking to make money that I want to put into global investment, it doesn't matter where I earn it. The absolute number is what matters. In reality, the number that matters is how much I can save, in absolute numbers, after taxes and cost of living have been deducted, but still the salary does not scale with cost of living. In that case, if I'm willing to maximize my investment, it's possible that I'm willing to move to the best paying country (i.e. the country where I can earn the maximum absolute number after taxes and cost-of-living has been deducted) for a while. "Global investment" may be quite broad and may include, for example, effective global altruism (i.e., asking the question "If I want to maximize my life's impact in improving others' lives, where should I work and where should I donate globally?").
Second, if we're talking about a job that is a seller's market, i.e., where I have has some very specialized skill, then the fact that the company is willing to pay double the amount if I happen to live in Silicon Valley but only half the amount if I happen to live in Romania, is pretentious. The reason is that the company is in need of my skill regardless of where I live and my acceptable business cost to them is a Silicon Valley salary. The difference from paying me less just because I happen to live in Romania is simply money that goes into their pockets. Why shouldn't it go into mine? In fact, if my skill is specialized enough, I should be able to negotiate for that, since their best next alternative may be a Silicon Valley hire.
(For clarity, the above are illustrative examples. I'm not an effective altruist, do not have such a specialized skill, and do not live in Romania.)
1-1,5k for high end apartment's rent (which is waaaay too much anyway), 400 for the car and 1k for other necessities.
If taxes were 33%, you'd be left with 66k.
66k - 12x(1.5k+400+1k+100) = 30k. That's still a lot more money left than if the person was in NYC without a lease/finance and with rent that's twice as much.
Most online comparisons are weird for two reasons: 1) they include the cost of car ownership, which is common in neither place, and 2) most rental apartments in London are furnished and in NY are not. I’ve seen comparisons for the cost of a furnished rental, but in NY you’d pay a huge premium for that. It’s also, of course, just plain hard to choose equivalent neighborhoods.
Reportedly, the rental market in London is even tighter than in NY. My friends say you can get a 1-BR or 2-BR for about 10% more than in NY (after accounting for exchange rates, and with housing stock / in a location that they consider equivalent to what they’d left behind), but it will be smaller simply because historically London buildings have been constructed with smaller rooms than NY ones.
Food in London seems to be more expensive than in NY. Medical care, of course, is less expensive. Transit is close enough to be a wash. Etc.