I'm endlessly distracted by other things at work, but I believe this same idea could also be used to provide real-time compilation of TeX'd documents as they're typed. Simon Rubinstein-Salzedo had suggested wanting something like a real-time Overleaf to teach his classes at https://eulercircle.com/ Interrupting and resurrecting the TeX-in-the-browser would let you render a document as it is typed.
Being born in 1981, the mid-2000s feel very weird to me too -- partly being in grad school in that time (and so somewhat isolated from the broader world) and yeah the rise of cell phones.
(There are so many plant metaphors in mathematics!)