Software people (generally) have a limited idea of just how complex and rigid customs enforcement can be. Moving physical product between countries is actually a very hard problem.
You cannot sell homebrew (and presumably won't be able to sell distilled beverages) without a very expensive license. Homebrewers (of all forms) are generally very aware of this when they get into the hobby. Even "cute" forms of recompensation are heavily frowned upon. The most I've seen are to "pay for the glass itself".
All that is to say, the government is not harvesting tax from homebrew.
Stardew likely qualifies for the reduced store cuts. Steam _lowers_ the percentage for a game when it sells high. Still somewhere between 10 and 25%, though.
Generally, the Steam cut is considered “fair” for Indy devs. The benefits of steam (discoverability, massive audience) generate more sales. My Indy dev friends are not upset about the steam cut at all.
This, however, is one area where eventually Epic Games shines — they take a much lower cut and if they increase in popularity with gamers then steam might be forced to lower their share.
Software people (generally) have a limited idea of just how complex and rigid customs enforcement can be. Moving physical product between countries is actually a very hard problem.