It's a shame as a user. I paid for the device, I should decide what happens on it. Apple doesn't have an innate right to store revenue.
Disallow installing apps from outside the App Store, provide no system UI to do so. Prohibit apps from being app stores themselves or running code that didn't pass app review, with exceptions for dev tools etc. Make apps able to escape the sandbox, at least in some ways.
Even if an app somehow sneaks past app review and gives users unfettered access to their devices, it can't ever get too many users. If it's unpopular, it's not a concern to Apple, if it becomes popular, Apple will know about it and can levy very heavy contractual fines on the dev.
The only phones that come with alternative stores are from Chinese manufacturers, which isn't going to be an issue for Apple as the operating system isn't open source.
> The legislation aims to prevent Big Tech companies from "self-preferencing" their own products at the expense of competitors.[3] Under AICO, covered platforms would be forbidden from disadvantaging other companies' products or services.
https://en.wikipedia.org/wiki/American_Innovation_and_Choice...