Agreed but even data sync wasn't unheard of before everything became a "web application."

I mean not to get really low level or abstract, but there's a reason that operating systems have the concept of a virtual file system. Where and how your data is persisted is something that can be abstracted from the rest of the system. Add CRDT or another conflict resolution solution to that layer and, I don't want to pretend that it's simple, far from it ... but it's not new tech is all I'm really saying.

Distributed systems were a very hot topic in the 90s. We even went through one very awkward and short-lived fad where we toyed with the idea of having a single application distributed across a network of computers ... not to persist data across multiple systems per se but for computation performance. This entire concept got abandoned when people realized how unnecessarily complicated it was (all cost / very little reward). But it was a thing for a while.

Even RAID distributes data persistence across physical devices and needs to care about data integrity as a result.

It just seems like the longer I'm in the industry, the more I realize that there is very little that is actually new ... despite the fact that we have a large number of enthusiastic young software developers who are looking at these concepts with starry eyes and youthful ignorance because they weren't around decades ago when this stuff was being researched, developed and experimented with.