After 30ish years of internet without it I would assume they got used to LTR.
It feels like this would cause a lot of bugs because devs aren't prepared to handle vertical correctly.
Vertical can be nice for poetry or prose but forms? I believe in Japan/China/Korea most signs, subtitles etc are LTR. Mongolian script is something else but it feels like bringing an antique custom to forcefully override some past Russian and Chinese imperial impact.
I really don't want to sound ignorant or xenophobic and would like to hear from someone native to this.