Sure. Basecamp, that gigantic greedy trillion dollar company, that doesn’t actually want Apple’s help to sell their service but need to provide their users’ with an app. Like every single company does.
And while Amazon aren’t minnows, there obviously isn’t 30% to give to Apple on the sale of a book where there are various other parties that have to be paid. It’s literally unviable.
Epic, is a special case where they don’t actually have any marginal costs and do just want more gravy for themselves.
Regardless, the end result is a shitty experience on Apple’s ecosystem, which they are implicitly endorsing through their rules and regulations.