According to a learned source I was talking to recently, the main reason for the soaring cost of anglo concertinas (which has far outstripped that of English or Duet models)has been the fierce competetiveness of the Irish Fleadh competitions.

As he put it, a good fiddler can get great music out of a (relatively)poor fiddle, but a concertina is a machine - even the best player can't make a poor concertina sound good enough to win a competition.

This ultra-competitiveness, plus the success of the Celtic Tiger economy which meant that a lot more musicians could afford to pay for top quality instruments, could have only one effect on the limited supply - to send it, as you say, through the roof!

Mind you, what is the "real value" of a good instrument? Top quality anglos are still cheaper than most benchmade fiddles, for example.