[michaelmrose]

Exclusivity is something the market maker buys from the vendor. Making such a transaction illegal does not in any fashion require the vendor to actually sell their goods on multiple markets it just requires them not to exchange money for exclusivity.

In particular I don't think it says anything at all about a situation where the vendor and market are not engaged in a relationship but rather are literally the same company. Nothing forbids a donut shop from actually baking AND selling the donuts.

I don't think a 3rd party Epic store is an example of tying either. It's not something you are being asked to purchase in order to realize the other purchase it is rather a means to actually receive the product you have purchased. You might as well say that <insert app> is tied to the purchase of an executable or disk.

Not only that but if Apple allowed sideloading they would arguably be able to trivially able to avoid even a misguided accusation of tying by providing a manually installable package file with the app store merely providing a free means to receive updates.