That's a little bit too narrow. There are lots of companies out there that manufacture products but derive a large percentage of their revenue from patents. For example, the chips that Qualcomm makes have been described by some as a loss leader to hide and justify their very lucrative patent licensing business.

That doesn't seem like a very useful distinction. Suppose new patent troll legislation comes along that would prevent enforcing a patent that isn't actively being used or developed (similar to trademarks). The trolls would just produce a cheap gizmo that depends on the patent in some way, and then blame the lack of sales on patent infringement. They'd colloquially still be called "trolls" based on a subjective judgment that they aren't really serious about selling the gizmo.

When someone calls Apple et al. a patent troll, I think it's from the perception that they 1) apply for overly broad or obvious patents, and 2) enforce the patents offensively. Also a very subjective definition, but it doesn't seem any worse than arbitrary "uses/plans to use" criteria.

I use that term for companies judging from how useless the patent they are defending is. Like "slide to unlock", "rounded rectangles of the device" etc.

Hopefully if the big boys get burned by trolls, they will finally decide to do something about the current patent system.

Apple getting trolled sucks for the rest of us too sometimes. FaceTime was going to be an open standard.