The Valve example sounds similar, but I think Amazon is comparably more nefarious:
Valve chargers developers $100 per title, and a revenue sharing fee that starts at 30%
in exchange, devs must follow Valve’s content and pricing policies (which requires developers not to undercut Steam’s prices
Amazon has a few different tiers for sellers, but in general, they charge:
Monthly fees ($39.99 / mo)
Referral fees (8-15%)
Fulfillment and refund fees, which includes additional storage fees
Advertising fees (for keyword bids or sponsored products)
Valve is kind enough to offer free promotion on the home page (if your game is popular, or has a sale), and digital games are much easier to scale, versus manufacturing and holding physical inventory. They also do a lot of nefarious shit (loot boxes…), but I’d argue at least their partners aren’t being squeezed quite as much.
https://x.com/sama/status/2027578652477821175