it's still cheaper to reprint it locally if the author is successful enough than to ship it from the UK to US or vice versa tho, current US editions of Pratchett are still being printed in the US

Reprinting is not quite the same thing as finding a US (or UK, this goes both ways) publisher who receives a handtyped manuscript and copyedits it much like any other manuscript they accept. As things still worked when Pratchett started writing (by the time of Discworld there were word processors)

I'm not sure if US publishers americanizing UK books is not a thing anymore tbh

It still is! It's a custom developped in the olden days when it made somewhat more sense. It's far more extensive with kids', Young Adult or genre fiction, or what's marketed as such; in 'high' literature they'll at most do the humor/humour stuff. It also varies by publisher.

Pratchett, apparently, being unusually strongly affected. (I couldn't tell, I've read perhaps half a dozen but some of them in German translation and all a long time ago.)

I read all of Pratchett, half of it or so in English and unfortunately a few of these in American English before I realized they were Americanized editions

at least they don't tend to do that in Spanish nowadays bsky.app/profile/ausi...