I think part of it is that hardware is tangible, software isn't, so for some reason people resent being expected to pay for software. Building software thus has less legitimacy in some peoples' minds. I see this in the retro computing scene: people will quite happily fork over large amounts of cash to have an old bit of kit repaired, or buy a newly-developed expansion for old hardware, but those same people - even the people doing the repairs and building the new hardware - can be incredibly hostile to the idea of someone asking for money in return for new software for those old platforms.