Against /tmp

I think the idea of a shared filesystem in general is bad. It’s not the 80s anymore where we’re logging on to a shared mainframe. Applications should be completely sandboxed from each other by default and only allowed to see what they need to see. Real sandboxing by default (not like systemd’s opt in sandboxing, which is an absolute mess) would eliminate entire classes of vulnerabilities.

This has been iOS's (and macOS's, for native apps) model for a long time, yeah. "Multiuser" computers are not common anymore, but computers with a bunch of apps/code that you put different levels of trust in (especially on a level on what you want a given app to have access to), now are.

It's very different from 20-30 years ago.

> It’s not the 80s anymore where we’re logging on to a shared mainframe

It's even worse than that: We're all using the same shared applications on some cloud.

> It’s not the 80s anymore where we’re logging on to a shared mainframe.

Modern high performance clusters still follow that logic, and are found in almost all large universities or companies doing research on heavy computational topics (artificial intelligence, comp. chemistry, comp. biology, comp. engineering, and so on)

macOS sandboxing for native apps has a long way to go to catch up with iOS. As one example, any application can read from your clipboard at any time. Web apps are, I believe, much better sandboxed.