I think FE has suggested the answer to this when he posted
"I suppose one way of dealing with that would be to ban the sale of imitation firearms".
Surely it would be no great loss to anyone if they were banned.
The problem with banning firearms is threefold:
1. if criminals want them they will get them
2. there are those who use them in a sporting manner
3. there are those who collect imitation items
It seems pointless banning something that is readily available to the criminal element as a result of smuggling (handguns) from Europe and elsewhere, preventing the legal use of firearms in a sporting role (target shooting) or removing the (apparent) pleasure gained by some in collecting replicas. Would it not be better to ensure the security of firearms held by the public, vet those holding them better and ensure that illegal possession had penalties that could not be ignored?
As far as the original post is concerned, it would appear that many of firearms stolen were from a collector in one action and of the others many were deactivated. Whilst I recognise that an armourer is capable of reactivating deactivated items, it does take both parts and expertise.
It is also worthy of note that I was once shown a .22 cal firearm made from the case of a metal Parker retractable ball point pen. Such an easily concealed and lethal weapon must be as dangerous (and useable) as any deactivated item.