Blame the WWW. The web wasn’t being planned that crappy - there were supposed to be backups and complete edit history. Vannevar Bush, Ted Nelson, and Alan Kay had the right approach, of which Tim Berners-Lee hadn’t heard of back then.

The sick sad history of computer-aided collaboration
https://www.quora.com/Who-invented-the-modern-computer-look-and-feel/answer/Harri-K-Hiltunen
(long story)