The definition of a byte today is different than the definition of byte when those machines were manufactured. Just like how 'foot' is now standardized(*)

(* technically, a 'foot' is not a standard unit of measure but that's due to the long history of 'foot' not being standardized until relatively recently)

No. 8 bit bytes are the de facto standard but that is in no way official nor the definition of the word. You can find modern niche projects with non-8-bit bytes (and by extension non-32 or 64 bit words).