I don't think it's necessarily ironic. I'd argue that the "success" of the mobile and web app paradigms are in large part driving the plain text movement. It's almost as if a tipping point has been reached, where the complexity thicket of siloed everything, hidden everything, subscription everything has pushed people in the other direction, more so than proprietary formats just by themselves would have been able to do.
Folders are hidden, no default text editor, lock-ins everywhere you look.