As we say in the blog post, the Jupyter Name has been around only since 2014, but the work started in 2001. So 17 years is a good check of time !
Though the part that people mostly identify with the project, the Jupyter Notebook was introduced only in 2011. I remember that vividly as I was writing my thesises at that time and spending quite some time playing around with it :)
Though the current notebook is the 6th prototype, so there've been quite some work before actually being made "public". Hope the notebook didn't distract you too much from your PhD !
If open source didn't distract from ph.d's, we wouldn't have had ipython! ;)
overnight successes are usually 10-15 years in the making; so much goes on before the public release