Comment by rafram
It really isn’t such a big deal. Switching to A4 would mean replacing every single binder, folio, cover, and clip in the country, and for what? A slightly taller sheet of paper? US printers can already print A4 if necessary without any issue.
I think the UK has done that - I have foolscap and letter folder from the 70s. And no we did not replace every binder, folio etc.
We just bought new ones when needed.