Some of the newer Piano Shaped Objects do simulate the sympathetic
vibrations when the sustain pedal is used.  There are also some PSO's
that can not be distinguished from the real piano if you happen to be in
a room next door.  General Music's newest piano has a good sample but the
touch is so so.  The newest Yamaha Clavinova's are really good also.  So
before you judge all PSO's as junk you need to look at the high end of
the PSO's that are being sold today.  I sell more PSO's to people that
can play than you would guess.  This has been a record  year for people
trading in their real pianos on the PSO's.
In this part of the country it is very hard to find Piano Tuners in the
small towns.  In this city there are only about five tuners left to
service pianos.  This area has a GSMA of 450,000 people.  The next
closest piano tuner lives 100 miles away. This is one of the reasons for
the PSO.  They do not need a piano tuner.  Not every one can afford a
Bosendorfer or Steinway so yes there is a need for PSO's.

Don Teach

P.S. They are great for creating MIDI files to make piano rolls.