The sad state of the Raspberry Pi software ecosystem (thekeywordgeek.blogspot.com)

Like he writes, Linux has tons of software. Raspberry Pi is part of that platform, not its own thing.

To me, the only interesting things that could be in a pistore like that are alternate distros (piplay, rasplex, retropie.. etc)

the open pandora had way more success with an 'app store', because it had a uniform interface and niche community formed mostly around gaming.

http://repo.openpandora.org/

That certainly doesn't have an officially sanctioned way to program for it. Just a community oriented around it.