Interesting that you would say that. I've taken the opposite approach to prefer languages that have multiple implementations, platform-independent specs, and a focus on portability, like C, JavaScript and very few others. Also Java/JVM, which at least fulfills this criterion on paper (and pays the bills). Guess it's a matter of whether you're working primarily on the server or client side.
Being platform languages doesn't mean they lack multiple implementations, platform-independent specs.
All the ones I currently use in some form, Java, .NET languages, C++, JS, SQL, fulfill the above via ISO, ECMA, or official reference docs managed by multiple vendors.
And to be honest, even those that don't I really don't care any longer, because most of the code I write isn't mine to own rather the employer, so as long as it fulfil what the customer is after, I am good, when the project is done I move to the next challenge.
If project requires cross platform capabilities, then usually something along the lines of what is available across all platform SDKs gets chosen.
