I am not sure when Daum started producing these, but I do know that it was still being offered in their catalogue in the late seventies, when my family were running one of the major Daum stockists in the UK. They weren't a great seller because they were priced at the top of the range and certainly stockists in the UK, didn't think they had sufficient oomph to sell for the expected retail price, which from memory was about £450 in 1978. I think we did buy one in 1979 and it sold.
I believe the flame was intended to be reminiscent of the everlasting flame under the Arc de Triomphe in Paris. Possibly the local market had more affinity with the subject matter.
I have no idea what the present day value is and it could well be less than the 1970's value, but the replacement value might well be higher. They were very well made, and their nature was such that no two would be quite the same, but their production was only limited to the quantity of orders received, so it may be that hundreds were produced and this might have a bearing on the value.
They were, however, vulnerable - the joint between the flame and the base would not survive a fall, so it could be that over time they may have become rarer. :rn: