I think time is the motivating factor here for
VB. The regional operation of these turbo props will be profitable, especially coming from operating the E170 (albeit on some different routes). If they had the time
VB may have considered doing this in-house however a few factors come into play.
VB are flat out- arrival of the A330, rebranding of the product, an agreement with Air NZ and Etihad etc. How on earth would they have the available resources to get this new type up and running in the required time frame?
It has been identified that the 170 is not working and needs to be replaced, asap.
Qantas have made a move out west and this is a necessary counter. Of all current stand-alone turbo prop operators in the country able to achieve this it seems to me that Skywest would be the pick of the bunch, especially as they are based in WA.
Just my 2 cents.