Well maybe stop putting advertising banners on my premium console's home screen for one.
Also, I actually don't agree with this. Having one store for a console makes it simple, and allows Microsoft to act as a sort of second quality control barrier. They wont allow certain game updates to be pushed if they cause certain problems on the hardware, and if another store is allowed then arguably that new store will have less protections for the end user.
On a PC or a phone it makes sense to have multiple storefronts because you use those devices for more than only video games. Not the same for video game consoles.
Nobody in the history of ever has said "Boy, I would buy an Xbox but only if I can buy games on the Epic Games Store."