The devs can just raise the price by 30%
Actually they can’t. Steam’s TOS has a “most favored nation” clause that forbids developers from charging less for their games on other platforms (at least this is how I understand it, I’m not a lawyer). From a small developer’s perspective, it sucks that they can’t unburden the player from the 30% where it doesn’t apply. From Valve’s perspective, that would turn Steam into an advertising platform for other stores.
Never look up the Hungarian name for the bassoon.