What is the purpose of reinventing an earth to LEO vehicle besides
providing juicy low risk contracts for the US aerospace industry when a
perfectly usable Soyuz is available off the shelf?

Yes there is a law that NASA has successfully used to support its not
invented here strategy, but the cost and time of Spiral 1 is an
enormously high price to pay for reinventing yet another wheel. Wheels
are useless in space.

Licensing or just buying Soyuz capability to ferry people to the ISS
for rendezvous with a real CEV optimized for space exploration would
move the schedule forward by several years and bring some excitement
back down to Earth. This would enable even more cost savings than
proposed by the Independent study for The Planetary Society which
recommends retiring the shuttle as soon as possible and speeding up CEV
development. Using this strategy a space based CEV could be operational
by 2010.

Study is readable he
http://planetary.org/aimformars/study-summary.html

The sooner we have real people making real voyages beyond LEO the
better!

"How inappropriate that this planet be called Earth, when it should
clearly be called Ocean." -- Arthur C. Clarke