Plus, if we could share the playlists with others, but it could only be accessed with a Sonos player, and they could be redirected to the website to discover what Sonos has to offer which is A LOT, that would create business. A lot of people dont know what Sonos is. 

While I like the concept, there is an extremely low chance that any of my friends have either the same streaming sources, or my local NAS based library. Which would make the concept of exporting and/or sharing a playlist a bit tough for the other ‘side’ to interpret. 

This would be a pretty cool feature.  

But IMO the chances of Sonos investing in new music playback features like this is probably close to zero. 

Export your Sonos playlist into soundiiz format, then anyone can import that into whatever music service they use.

Or export in Sonos format and they can import directly into their Sonos system, though would only work if they used the same music service as you.