I have resisted participating in these on-line debates until now, but this is
to easy a target.

The process that you suggest is available currently.  The machine required to
do it is extremely costly, and the through put is very low, resulting in a
very, very high capitol cost per unit of output.  

The current system is very low cost.  It could be improved a lot, if the
photool used to expose the photoresist was glass, instead of plastic, and
that too is currently available, and occaisionally used, but it is very
costly too.

The purchaser of PCB has pushed the fabrication industry to the limit cost
wise,  and even more service wise, it is time for the user of the bare board
to pay for the increase in quality that they are demanding.  All things are
possible, all it takes is money.