Unlike Windows there aren't external drivers for most things. So you don't
have to search for drivers and insert disks as in Windows. The detection is
done by the kernel and the drivers are supplied either at that level or with
the distro. Ubuntu 9.04 uses a different kernel from 8.10 and Canonical must
fit everything onto a CD.

To keep things from ballooning things are pared down and decisions are made.
Sometimes things are left out by design and sometimes it is an oversight.
Otherwise things would swell to unwieldy proportions and people would
complain. Different versions mean different decisions were made. There is no
way of knowing whether your hardware was an oversight or a deliberate
decision. You can't please everybody. They get complaints either way.

There have been ongoing discussions about Ubuntu moving to a DVD, but so far
they have resisted. At some point tough decisions will still need to be
made.