I have zero intuition why online stores charge 30%. Is that fair?
Should the store's cut go down with more volume?
Or should smaller, younger, lower volume vendors get a better deal?
I have no idea.
So I keep landing on the notion that online market places should be not-for-profit orgs (consortiums?) that are run at cost plus some margin. And then figure out the hosts' cut from there.
Is charging 30% fair?
Another point to make is the added visibility. ArtStation for example is quite prominent in the art / 3D world, whereas Steam is unavoidable as an indie dev. Itch.io takes a much lower cut, but it doesn't bring in even close to the amount of viewers as Steam does.
I now realize I should have been asking if 30% is "reasonable".
For you, absolutely, and I appreciate your explanations.
• The operating costs are very low, since all Easyful does is email your customers your content when they buy it.
• Our team at nicer.io is primarily a product agency, so when we make our own apps like Easyful, SimplePerks and Smallchat, they don't have the pressure to be highly-profitable. We often end up getting good connections, agency customers and referrals from these apps, and keeping them running and supported is pretty low-cost for us.