Python languished as an obscure niche language from its inception in the late 80s until at least 2000. I recall discussing it with friends all during the 90s to blank stares and shaking heads. Rapid adoption (of, well, anything) is a network effects game. In the very early 2000s Python really took off (basically Python 2.x).

It surely helped that well known companies like Google (pre-IPO, "ad free & proud of it" back then) started openly saying they used it, but like many network effect things, it's probably hard to pin down any one "cause" (but easy to fool yourself into thinking you have, e.g. Google also said they used Perl). The Numeric module existed, but data science was not very strong until Travis united the numarray/Numeric things into NumPy. [1]

https://en.wikipedia.org/wiki/History_of_Python has more details, but it does not have a nice plot/chart of "How weirdly do your software friends look at you when you bring up Python..." which has, shall we say, a "data collection problem". :-) Proxies for such data might be interesting case studies in the sociology of programming languages, though.

[1] https://en.wikipedia.org/wiki/NumPy

Actually a really good point! I entirely forgot about Ruby! Though in terms of competition that does still seem less crowded of a field as one where your other contenders are C, C++, Rust (and for application and web-development there's also Go, to some degree also Java and Python)