My understanding is that you want to distribute via your own store you need to develop your own distro, reverse engineer their backend, develop your own backend. Develop your own forked client that actually searches in more than one store and then you can distribute to only those people running at minimum your forked client.

Basically if you have multiple millions of dollars you would be able to distribute your software to probably nobody.

Compare this to making a repo for any platform that allows multiple repos where this is fantastically trivial.