The parent comment stated the best solution was to allow both an app store and consumers the choice on how / where they get their apps.
If the default app stores provides as much value as you claim, developers would continue to distribute there, pay the fees, and consumers would go there for discoverability and convenience. Let consumers decide.
With options, consider maybe someone could provide those services even better / more cheaply and you also benefit as a developer.
The App Store is also a service for distribution. If it wasn't there, I would be forced to invest much more in marketing, cloud services and all kinds of "small things" which are not the primary purpose of my apps. If anything, my apps would be more expensive outside the store.