Uh, adoption by the community at large? The best program is the one you didn't have to write because a package existed for it already. Just because a language has a foreign function interface doesn't mean it's easy to interact with other libraries.
R, Python, Matlab, and C++ are the big dogs in scientific programming, and the inertia behind having a large community behind than will continue to drive adoption.
In a great many cases, they aren't a first-order issue - which is where my objection to a blanket "don't waste your time" claim comes from.