[henryfjordan]

The legislation would require Google/Apple to "step aside" and allow side-loading/alternative app stores, so yes?

Google and Apple would still be welcome to operate their own stores. A 3rd-party cross-platform store would compete with them, hence no monopoly.

Edit: I guess you read my comment to mean "Apple's app store would come to Android" or vice versa? That's a possibility. I'd prefer that to the current state of affairs where no direct competition is possible

[shimfish]

I still end up with one more app store to deal with. Unless this 3rd party becomes a de-facto monopoly, there's no way you could afford to leave money on the table by not also dealing with Apple and Google.

[Apocryphon]

It doesn't at all. You can continue to just publish your apps to the App Store and the Play Store, much as the vast majority of users will continue using those.