This kind of answer really ignores almost all of why these languages have done well. They are easy to learn. Relatively speaking, especially at the time they we

This kind of answer really ignores almost all of why these languages have done well. They are easy to learn. Relatively speaking, especially at the time they were gaining popularity, they were far easier to learn gradually and still be productive than almost everything else available. Their communities adopted explicit "this language is for DOING shit understandably, not golfing, not squeezing cpu cycles, not researching type systems, not timtowtdi, etc." That helped tremendously. In pythons case, it was very easy to wrap up C and C++ code and lift it into a nice environment with a repl and everything else you need to experiment. This put it in an excellent position to grow along with the scientific community. Numpy was a huge asset here. The rise of rails, Django, heroku, MacBooks as the dominant coding environment etc all fostered an environment where coding went from being nerd shit to being fashionable. This ushered in the era of "people who code for reasons other than being huge fucking computer nerds," in which the benefits of Python and Ruby mentioned above became even more relevant.