Probably not quite what you meant, but most of the kernel developers are paid to work on it full time (and by most I mean >90%, last I heard). Whilst that is n

Probably not quite what you meant, but most of the kernel developers are paid to work on it full time (and by most I mean >90%, last I heard). Whilst that is not a business in the same sense, there is business around enough to make it worth while.