I'm not (yet) using Bitcoin, and I'm just approaching this world as of now.
I stumbled upon some merchants that sell mining hardware (with some GH/s). But I've yet to understand what they gain, apart from the upfront cash.
The reason one should buy mining hardware is, if i'm not mistaken, to "generate bitcoins", i.e. "generate money"; so, one expects to be able to have a return of the investment sometime in the future, so I guess that in some way my claim is correct (about "generating money").
But then, why don't the companies simply use their own hardware?