People neglected the fact that having $HOME access was already bad enough and lived in the illusion that running applications as normal user was safe.
Why is having a home directory bad?
Any application running under the user id has full access to his private data.
Add the capability to do network communication and suddenly the all wolrd has access to $ HOME.
This is why in the container model of mobile OS and Windows/Mac OS X sandboxes, applications only get to see file handles to files choosen by the user.
I'm hearing this argument from time to time. But I'd like to know what exactly changed. I can think of a dozen use-cases for which a shared, system-wide filesystem would be absolutely necessary (yes, especially with computer-illiterate friends and relatives, as "files" is pretty much the only abstraction besides "web" that is widely understood even outside of "geek"/"power user" circles).
So, what exactly has changed between then and now that made those use-cases legitimate in the bast but not anymore now?