Have to remember in England language use and spelling grew up organically.
Not taking from Greek or Latin roots but more influenced by the versions of French, German, Danish, etc... from which English people first heard them.
A very democratic development of language.
By the time America came about more people were reading and writing and spellings were being laid down in the dictionaries.
Perhaps the Americans wanted to standardise (ize) the language to make spelling easier both for native and foreign learners.
Also in the case of schedule where Americans hark back to the Greek roots there's pseudo-intellectualism/intellectual oneupmanship. "We're not backwards hicks. We know Greek and Latin just like you, and how to apply them. Hell you can't even pronounce ",schedule" correctly! It's from the Greek stupid."