It actually makes a lot of sense, because the change to Scala was triggered by "Simon". Another Simon will come and bring Python or something even worth.

That's incorrect. The technology change was bottom-up, by developers. Simon didn't intervene with his technical direction until we already had a couple of Scala projects under our belts.

I you saying you had a vote and some developers (C#) disagreed and there was a minority of them?

There wasn't really a vote, but we did have a group forum where objections could be raised. People who weren't onboard with Scala were in the minority and most of the arguments raised didn't hold much water.