[sirclueless]

That would break compatibility with a lot of existing scripts, which look for things in /bin, /lib, /usr/bin etc.

There are specific reasons why having a single mount point for all OS-provided binaries is a good idea, for example because maintaining a split that differs across distros and unixes is a maintenance nightmare. The main counterargument -- that it is desirable to have a minimally functional system without /usr mounted -- has been obsolete for years.