Initially they were cool, seen on the best bikes, in the right mags, in the top shops. In my eyes though their products weren't innovative or novel and just broke too quickly in comparison to others. Hubs were just bullseye copies, frames were standard generic ti fare of the time, bars were just reworked canoe paddle shafts. I had almost every set of ends returned to the shop, most every other hub set cracked on the flanges and most bars just frayed to pieces or failed. As soon as that happened the only people who rode the stuff were the 'all the gear, no idea' guys and so their cool deminished.
After that they sold out, pumping out generic stems and guff, cool level falling...Finally they totally sold out with rights to the name going to some far east parts house, no cool left at all.
In my view the cool brands are the ones that burn bright and die quickly not like Nuke Proof that's still trying to hang on with dull products-it's a bit like the Cliff Richards of the bike world.
Your statement can be applied to pretty much every chi chi MTB brand from the golden age of mountain biking (arguably 85-95). Don't know how that figures into it being cool at one point or another.
Cool is many times trendy; trends don't last. When items that are cool and trendy attempt to become a more stable and lucrative item, it many times loses its cool, selling out or just falling out.
This is not the What Works Wall. Nuke Proof in the context of Retro, (not their modern incarnation), is cool.