Xamarin was also closed source and $1000 per platform per year (my employer at the time was paying $3k/year for the mobile devs to churn out iOS, Android, and Windows mobile apps from one Xamarin code bas). Immediately after being acquired by Xamarin the price was dropped to zero and it was announced that the entire Xamarin platform would be open-sourced (and this promised was fulfilled less than a year later).

This is not the Microsoft of Balmer where Linux was called a cancer. Under Satya Nadella the company is serious about providing the best office and cloud products regardless of what OS you use.