A language is just a specification. Anyone is free to implement a compiler / interpreter for any given specification. For example, Mono is an implementation of the .Net spec. It's not a very good implementation, but it's one, nonetheless. The same with IDEs, debuggers, and all the other trappings that some programmers mistakenly conflate with the language itself. For example, Komodo is for-pay, but it's a Perl IDE. Does that make Perl "free" or not?

I think your question should really be: "Will F/OSS language infrastructure continue to grow or not?" And, the answer to that is "Most likely." The big question is whether or not the support that's needed for large-scale public adoption of these technologies will keep pace. RedHat doesn't sell Linux - it sells Linux support, infrastructure, and knowhow. Will there be a similar offerings for other items, like GCC and/or Mono? That's the key.