I read Troy Taylor's posting on this subject (14.07.17) and I think he
makes a number of very pertinent points.  The reasons for the decline
in the market are complex.  Troy identifies shortage of specialist
tools for potential restorers as one reason.

Leading on from that, I would add that the advent of the digital age
means that people are no longer exposed to everyday items which are
programmed mechanically.  Once upon a time, if something failed to
work, there was a tendency to open it up and see if you could fix it
for yourself.  My late cousin learned how to fix old clocks and watches
more or less by experimentation when very young, and went on to restore
old cars and even repair the odd musical box.  Nowadays there is not
much the novice can do if it's the electronics which fail, so there is
little incentive to investigate how something works.

Proportionately there is less industry now requiring trained engineers
than in former times, and consequently fewer people learning those
practical skills as part of their trade or employment which may have
led on to their becoming hobbyist repairers/restorers, or curious as to
how a mechanical musical instrument might work.   For the most part I
would imagine that unless the observer has some idea of the scientific
or mechanical principles involved in the construction and operation of
an automatic musical instrument, concepts of precision or ingenuity no
longer impress as they used to a couple of decades ago.

I have never 'collected' for investment purposes; for me, the 'value'
of an instrument is in direct proportion to the pleasure it gives.
My main concerns are that after I have gone there will be someone who
will enjoy listening to the instruments, willing to give them house
space, willing to share them and, as Troy says, someone with the skills
(and the tools!) to ensure they keep playing.

Alison Biden, UK