The 40x rent is for a unique time with a 1% vacancy rate and NYC being the only job engine East of Hollywood.
This is something VERY new and mostly for chi-chi new housing in Manhattan.
Many are paying 50% of their salary in rent, many are in very low rent stabilized apartments which are NOT government subsidized, only regulated.
I fully believe the data that half of New York households are making below 48K and probably 90% are making less than 100K.
I also believe that VERY FEW renters have ever been exposed to the 40x rule. I have gone through several boom-bust cycles and I can attest to times where most landlords were deliriously happy to get a tenant who could pay a month's rent and security deposit. Many of them are still in their apartments.
Remember too, that an immense number of people live in New York and are retired living MOSTLY on their social security checks (unless they worked for the government.)
In NYC the rich are VERY rich, the poor are very poor and the middle guy is not very well off, worse off actually than the rest of the country.