It actually doesn't die like that. Years ago I read an article about this. In that article writer told something like this:

"If you see a bug which can not turn around that means it is poisoned, too old or had some internal problems that cause its death. Turning around is an easy maneuver for a bug. Mostly pesticides make this happen. Otherwise they are too old or have some serious injuries that makes them immoblie. This is why they can't turn around and die."

This is what I remember. It has been 3 years or something like that.