You're oversimplifying, a lot.
First and foremost, the terrain path is actually more favorable from Philadelphia than from New York to Tom's River, at least according to the standard propagation models. Distance isn't everything; if you're blocked by an obstruction, there's really nothing you can do about that; distance doesn't matter at that point.
Second, the power levels in Zone I are:
305m 10 kW
305m 30 kW
365m 1000 kW
Scaled downward accordingly if over the height listing. And these are upper limits assuming that a station isn't limited sooner by interference. From this, you should immediately see a few things. First, WABC, WPVI, WNJB, and WBPH all have waivers of the power limits. Those stations have agreements with other impacted stations to receive excess interference and successfully received waivers of the power limits from the FCC.
WHYY, WJLP, WACP, and KJWP, by contrast, operate right at the FCC power limits, when adjusted for their heights.
The odd men out, here, are WPIX and WNET, which operate below the FCC power limit, which for their heights, would be 11.7 kW. This is due to interference restrictions, where WPIX and WNET could cause too much interference to other stations. And, for that matter, 7.5 kW and 9.3 kW aren't that much weaker; less than 3 dB.
As far as UHF, in a cluttered area like the northeast, it should come as no surprise that interference limits station coverage areas. Stations like WPXN/WPPX, WNYW/WMCN, etc. are co-channel to each other, which harms reception in the overlap areas, while even stations that aren't that close together may also have to restrict their power or operate directional antennas to avoid interference.
- Trip