Airline Alliances Vs Joint Ventures: What’s The Difference?

In some countries, turboprop aircraft are commonplace. However, in the US, they seem to be far less common these days. Sure, there are a handful of US carriers out there operating turboprops. But, overall, have such aircraft not proved popular in this part of the world? Particularly as they have seen relative commercial success in other regions? Factors such as geography and passenger perceptions have all played a part.