It's probably because Steam has an entirely different set of rules and format for games to be posted there. I'm no coding/game making expert, but I'm sure there were a lot of changes made to the games coding and design behind the scenes that we don't see. They had to make a lot of adjustments to the game for it. Honestly for all the time and effort that went into it, I think the current price of the game is a steal 🤷🏾