I believe that in the 1920s, mechanical music, mainly the player piano,
was definitely a significant part of the social fabric of nearly every
country on Earth.  But, much time has passed since those days, and
a vast number of machines that were made no longer exist.  Today, life
is faster, attitudes and interests have evolved, and the day of the
player piano has long passed.  Mechanical music groups cannot expect
large memberships, based on these facts alone.

There are still literally thousands of piano rolls offered each year on
eBay, plus newly made rolls (albeit in relatively small runs).  Dozens
of instruments are for sale and purchased each month in a variety of
media.  These items have mostly survived 80-odd years, and the large
numbers still available are only remnants of what was a very popular,
profitable and massive medium at that time.

However, as with any interest or hobby, there will be collectors,
restorers and admirers, though they may be in ever dwindling numbers,
until the last unwanted inherited instrument is deposited at the dump.

Regards,
Paul Brennan