A helmet doesn't have to compres to protect you. In that accident I took a very heavy and direct hit to the head and then a lot of scrapes as I rolled. Even though my helmet didn't compress as such it spread the force of that impact out over a larger area, and even after the liner cracked, the shell kept it together and it still protected me from whatever else I hit. Had the impact have been direct onto my head, I don't really want to think what the consequences might have been. Don't assume I had no benefit from wearing a helmet just because it didn't crush. It takes a lot of energy to break a helmet, and the energy it took to break mine was energy that would otherwise have been directly on my head. I know that helmet saved me from some kind of injury. How bad an injury I'm not sure, but it definately saved me from something.

Incidentally after that I decided to only wear hard shell bmx/skate-type helmets, just because they're quite a bit heavier and are much more solid. When I put my helmet on it's very important to me that I feel like I'm wearing something that really will protect me if I need it to, and my TSG Evolution does make me feel very safe. I haven't done a ride without wearing a hard shell helmet or my full face helmet since then (probably 5 or 6 years ago), and I never will.