I think the issue with paying for a Nethack game is more about production. They guy isn't making any money really. I think a print and play style version would have been more appropriate.
Unlike with video games, table top distribution can be tough unless all the components can easily be printed on card stock and cut out. Dice, pawns and other things often aren't available to the end user.
Computer games really are superior that way. Very very accessible and easy to start up. Even the simplest table top game takes effort to print and play. And most people won't do it no matter how awesome the game is. You can't even get people to fiddle around with libraries and what not to get a computer game to play most of the time.
