Relying upon a machine that is so complex and frustrating to use far outweighs the tiny loss of revenue for when people pass on unused parking time to someone else.
Somehow I thought the opposite, I was sure that my layout (Hungarian[1]) is about the same as every other, most probably a direct copy of the German, but nah.
[1]: https://duckduckgo.com/?q=hungarian+keyboard+layout&iar=imag...
[1] https://upload.wikimedia.org/wikipedia/commons/8/88/Olivetti...
His explanation was that they did not use AZERTY or QWERTY because it wouldn't work for foreigners.
There's only so much one can do to defend a 1mm slot that has to accept a plastic card (ditto for coin slots).
I'm guessing at their reasoning, but "everyone knows QWERTY" is probably not as true as you think, or if it is, it hasn't been so for that long.
It could also be an international company that doesn't want to have SKUs for the keypad for every region (eg France uses AZERTY).
But you also can't name a layout which is more familiar than QWERTY, and its regional variants (including AZERTY).
If you don't want to localize, US QWERTY would probably be the single most familiar layout globally.
It's not like these are machines from the 90s when not that many people had computers. The addition of the keyboard is specifically something that was done because wireless internet and computer vision improved enough to do away wit the older version.
I'd be earnestly curious what percentage of the population that lives in an area with controlled parking like this doesn't interact with a keyboard at least weekly. Even my 99 year old grandfather was sending emails from his computer a decade ago from his farm in the rural US. The target demographic here is A. People who own cars B. who need to park them in urban areas with street parking. Both of those are, for the last decade, likely to own a smartphone, I'd imagine.