This isn't as easy as you would imagine, Steam takes a 30% revenue cut from developers, whereas Itch.io takes a default 10% that the developers are actually able to configure themselves. It is more intuitive for indie developers to start on Itch than it would be on Steam. Realistically speaking, the price to pay for both versions is probably more than accurate for a game like this, because a LOT of work was clearly put into it. I get it can be frustrating, but these decisions are completely justified.