Enforce antitrust legislation and caselaw, and force manufacturers to stop artificially limiting competition and consumer choice.
But crucially, you can sideload, you're not tied to an app store.
Can you load your own OS? Can you use your own VR client to connect to VR spaces? As mentioned in another comment, sideloading is against the ToS and clearly not at any kind of parity with Facebook-blessed app distribution channels.
You can link it to your desktop using Link or Air Link and use whatever VR apps you want there. I use it for iRacing amongst other things.
They've made moves that telegraph limiting this. There are now warnings every time you run a sideloaded app that doing so for reasons other than active development is against the terms of service.