If you want to start to sell ebooks (or anything really) you get an advantage by placing it in a well known store, you can prove me wrong but i think that is a fair statement.
So it is really hard for me to accept as fair a situation where you could build a store, build the brand reputation, host other people product and not get a compensation.
If you think the Apple Sore brand or "top apps" is important then have extra options (like web hosting). So I might not want my app to be promoted, I just want my users to be able to install the app I link from my website similar how they can install it on their PC. If my updates are eat6inb bandwidth then I pay for that, if I want to be promoted I can pay for that, if I want support I can pay for that, if I want an IDE I can pay for that etc.
I think you are putting popular apps like Netflix,Epic,Dropbox, my bank thagt have no choice to be on all platforms with some small video game or TODO app that benefits by getting exposed to people on a "Top apps" or "Similar apps" screen.
Also I don't believe Apple is incapable of creating more fair rules(maybe you can't come up with this rules but Apple has the money to spend on smart people to work a few months on this) they don't want to do it.
If I get kicked off of Epic’s platform. Where do I go?
Steam, GOG, Windows Store, itch.io put your app on mega/GDrive,Dropbox and share the link on Facebook and Twitter should I continue ?
Why does Epic get to be the only company that can sell virtual currency in Fortnite?
What if instead of buying apps with money, Apple made everyone by “Apple points” to buy things on the App Store like MS use to do?
There are more then 1 alternatives to Fortnite but I can't name them. This is a bad example, you compare 1 free game with a store. Stay on topic and let/s compare stores like Google Play, Steam, GOG etc. Is Steam taking 30% if you buy some skin in a game? Is GOG doing that? Are this stores blocking you showing a text with a link to your website purchase page?
Party B, after using your premuim service, decide he will use your service just as a frontstore, sending your customer to his own website to complete purchase.
in your opinion that is a fair situation?