The one thing I don't understand about the Yun and Tre is...

Paul__B:
The Arduino - as a whole - represents a "hobbyist" and "low end" commercial market.

However successful it undoubtedly is, it pales into insignificance beside the "real" markets. ...

I fully agree with you. But that the Arduino could use a "best of both worlds" component surely doesn't imply at all that it is the only application that could use such a component.