They talk about how it was never actually possible to do this before, because it requires very fine “electron optics” and manufacturing of components, like slits and shutters, with nanometer precision. So while the thought experiment with electrons itself was proposed by Feynman in 1963 (which is probably what inspired the monkey meme and the like), it was not actually realized until 2019. I’m also now guessing that the electron quantum eraser paper from 2014 doesn’t use a double slit but some other electronic quantum circuit that is easier to work with.
The two-stripe photo to match the monkey meme, with electrons and measuring which-way information, probably doesn’t exist yet. So that’s why!