What the numbers mean
A $75,000 salary in New York City gives you $35,936 in purchasing power after state income taxes (10.4%) and local cost of living. The same salary in Phoenix gives you $65,290 — +82% more.
Median rent in Phoenix runs about $1,550/month — roughly $1,650/month less than New York City's $3,200. That's $19,800/year back in your pocket before anything else.
New York City's cost-of-living index is 187 (national average = 100). Phoenix's is 112.