How did those "developers" choose that change if a lot of them disagreed and left later on? There had to be 1-2 leaders who happened to be Scala-fans.
It wasn't too difficult to convince the CTO that Scala was the right choice. He's a big OSS advocate. From a technological perspective we were trusted to make the right decision.
I think what really sold the the rest of the management team was how much money we could save in licensing fees.
Come on, ...Microsoft licensing costs are a rounding error compared to the cost of developers.