I came across this very interesting interactive graphic that is an attempt at depicting the relative importance of a range of computer languages: http://githut.info/ It’s 18 months behind but still relevant. As you mouse over each language (see the example below) you get a line connecting its ranking on various dimensions related to its use by developers (slanted towards Github but still more objective, I think, than the Tiobe rating, which is based on website and Youtube “hits.”
Here’s why I find it interesting: It seems to me that what is happening “on the margin” is a good predictor of the future (and not just with computer languages).
Languages rise and fall in popularity. Rust is tiny in its relative number of respositories but ranks third in “pushes per repository.” My own informal observation is that some very capable people are working very hard within this language, and therefore I would bet that it will become more dominant in the next five-ten years. Someone getting experience in it now will be well positioned for employment in that time frame.