A lot of this is driven by historical concerns of large institutional installations that don't really apply to most Linux users today. We're set up for the pos

A lot of this is driven by historical concerns of large institutional installations that don't really apply to most Linux users today. We're set up for the possibility that /usr is a read-only NFS share for use by multiple processor architectures. This is an increasingly rare scenario, but it's the justification for why /var was split from /usr and /usr/share was split from /usr/lib.