1% market share is huge. webOS barely had 1% when they launched their third device out of an eventual total of 6. webOS was critically lauded and meant to be used and accessed as you saw fit. No blocking of the homebrew community. I know you're proposing something different, but if webOS was around 1% market share in 2011 in the middle of their device launches and when smart phones were still in their relative infancy...I don't see much chance of an OS like you describe grabbing .5%, much less 1%.
The issue of apps will always be an issue. No matter what commmunity you go to, most people will probably want at least one of a number of popular apps that won't be on this OS. Some can be reverse engineered or use hidden APIs but not always.
Examples being: Messenger, Whatsapp, Snapchat, most other messaging apps or video chat apps like Skype or Viber, Instagram (website doesn't have tagged photos of people or uploading), Pandora, Spotify, Netflix, Hulu, basically any tv sort of app, most dating apps like Tinder, Shazam, and any major mobile games.
The issue of apps will always be an issue. No matter what commmunity you go to, most people will probably want at least one of a number of popular apps that won't be on this OS. Some can be reverse engineered or use hidden APIs but not always. Examples being: Messenger, Whatsapp, Snapchat, most other messaging apps or video chat apps like Skype or Viber, Instagram (website doesn't have tagged photos of people or uploading), Pandora, Spotify, Netflix, Hulu, basically any tv sort of app, most dating apps like Tinder, Shazam, and any major mobile games.