NYC is unique among large markets in the U.S. in that it has fewer full-power commercial FM stations. 93.9, 99.5 and 105.9 (not full power but on the Empire State Building) are all non-commercial outlets. That leaves only 16 FM signals available in NYC. 94.7 had been another non-comm in the commercial band but its sale has finally given NYC a Country station after so many years without one. LA has only no full-power non-commercial stations in the commercial band. (There is one religious station, KKLA-FM 99.5, which used to be non-commercial but now is a Salem brokered preaching station, with some commercials.) LA has two NPR News/Talk stations (but neither full power), a classical station and a Pacifica station, but they are all below 92.1.
Another problem is that NYC is in Class B territory. So no station in the suburbs can pretend to be a market-wide station. Go to Dallas or Houston and they have stations 20 or 30 miles from downtown, in the .4 MHz, between the major FM stations, that get programmed like they are market-wide stations. Some run 100,000 watts on high towers and get good ratings, even if they miss some parts of the market. NYC has only a couple of 50,000 watt stations in its suburbs. Most suburban stations are powered at 3000 watts. They can only serve their specific region, not NYC. I can only think of one exception, Christian Contemporary 99.1 WAWZ Zaraphath NJ, which acts like its a NYC station, even though its signal is poor outside New Jersey, Staten Island and Brooklyn.
In LA, several suburban stations have formed simulcasts, often getting ratings equal or better than some LA stations... I'm thinking of the 94.3 K-Buena stations, the 107.1 KSSE stations, the 103.1 KDLE stations and till recently the 93.5 KDAY stations. For a time, NYC had one trimulcast at 107.1 doing country music. But it eventually broke up.
I'm sure if there were more signals available, someone would do Alternative or Active Rock in NYC. Or maybe some other formats not currently heard.