Apple just kicked Fortnite off the App Store

I don't see the problem, Epic explicitly went around the app store's payment process and terms of service. It's within Apple's right to pull Fortnite. They are also suing Apple as well.

Why should Epic get a “special arrangement” from all other developers?

If you don't like the terms, then don't be on the Apple App store, but of course your missing a huge swath of the population thus the 30% fee. Being on the App store is essentially unlimited marketing and exposure for your app. Cost of doing business.

As a consumer, why can't there be an alternative App Store on IoS if I don't like the Apple terms? Apple shouldn't force consumers and developers to provide them with 30%.

There is - buy the more popular, larger market share Android phone and your problem is solved.

And have the same issue with Google Play? They also take a 30% cut.

Google Play is allowing Epic to do it. Fortnite is still on the Google Play store.

(The writing has been on the wall and Google is already adapting - they sent out surveys last month to some developers about dropping the 30% fee and charging developers an annual listing fee instead - possibly also fees for bandwidth/storage used like a hosting company does. The survey also mentioned plans to spin off the Google Play store as a separate non-Google company.)