I would have picked the same small set of LA parishes as "most livable."
And yes, one has a higher quality of life in NYC -- with the exception of the Bronx -- than anyplace outside of the gated counties of the South (Forsythe GA, Williamson TN, etc.).
But these sorts of gross county-level comparisons are sort of misleading. Zip codes are a better measure of class stratification than counties are.
One needs not live in a "gated county." I'd much rather live here in leafy East Memphis than some distant, treeless subdivision. I know a little something about quality of life. Paying $2,000+/mo for a 300 sq ft studio doesn't stike me as an "easy" way to get by.
It's "easy" if you make enough money, which plenty of people in Manhattan do.
To some people, quality of life entails more than getting a big house and filling it with junk.