[arghwhat]

It is a matter of requirements. A login may require LDAP or Kerberos, which requires network connectivity. Pulling up network before the firewall is initialized could be dangerous. Maybe your desktop environment needs to play a jingle, so it by default waits for sound to init.

Service optimization is basically deciding what your system doesn't need in order to function for your usage, and moving things you don't need to a late initialization with no dependents. A distribution dedicated for a particular machine usage and desktop environment could do some tuning on your behalf, but it is not generic.