If you want to focus on something and be a happy expert on it, but don't want the insane license costs and lack of freedom, Java + Linux/BSD is a superb alterna

If you want to focus on something and be a happy expert on it, but don't want the insane license costs and lack of freedom, Java + Linux/BSD is a superb alternative. It gets you the same familiar, consistent platform, IDE support, performance, and do-anything-ness, while being much less restrictive. There's nothing that platform can't do that Microsoft can't, and you also get the option experimenting with interesting JVM language alternatives like Scala, Clojure, Kotlin, JRuby, etc, if you ever get bored of pure Java.