LSAM

Don't know if this has been discussed before, but I noticed some time ago
that the LSAM will be discarded after it performs its duties. What are some
thoughts on a less wasteful approach:

1) An LSAM that travels between lunar orbit and lunar surface in one piece
(reusable),
2) A CEV that goes from ground-to-earth-orbit-and-back ONLY (crew taxi),
3) An Earth/Moon transfer vehicle that ONLY goes between earth orbit and
lunar orbit (reusable; stationed at ISS),
4) A fuel/cargo/resupply transfer vehicle that takes stuff anywhere.

Maybe this is too complicated, but it seems wasteful to me to throw away one
LSAM for each access to the lunar surface.

Jon