Nope, not all true: tax deductions are pretty much the same for Coops and Condo's, except if the Coop violates certain IRS rules like the "80/20 rule". Also, a lot of Condos are developing complex sets of rules which makes them more and more like Coops (quite ironic, actually, but it's because people who buy very expensive apartments actually want "restrictions", no matter how much they complain about Coops being restrictive).
Getting back to Coops in NJ: from my experience, the Coops in NJ are "lesser" buildings than the condos: the condos are glitzier, high-rise buildings with lots of amenties, and teh Coops are dumpy 1950's and 1960's buildings which were never "top notch" even the day they were built. So, they start off not being too desirable, and then you tell the buyer "it's a Coop", and it gets even tougher. For example, I know when I looked at stuff in Teaneck, the Coops were all in dumpy buildings.
But again, it's mainly what people are used to: look in parts of Brooklyn and Queens which are "equivalent" (economically, demographically, etc.) to Fort Lee, and Coops still sell fine.
One other issue: who is doing the buying? I don't know about today, because I haven't venture into the Fort Lee market recently, but when I was in that market: you had a large percentage of Asians - Koreans in particular - seeking to buy the Condos there. At the same time, when that sme group was seeking to buy in Manhattan, they would only look at Condos there as well. So, if they make up a small percentage of the marlket looking in Manhattan and they will only look at Condos, it doesn't affect teh market all that much. But if they are a major force in the market somewhere else (like Fort Lee), that could have a major impact in the smaller market.
When teh market crapped out last time, it because almost impossible to sell Coop in Forrest Hills unless they were in "top buildings". One reason was that the few peple who were still in the market to buy, only wanted houses, not apatements and certainly not Coops. the biggest single thing which moved the Coop market back up in the "lesser" areas in Brooklyn and Queens (i.e. not Brooklyn Hieghts, Park Slope, etc) is that people who wanted to buy (especailly first tiem buyers) could no longer afford even the bottom of the line houses, and still wanted to buy, so Coops were the only choice.