The truffle is appreciated by some people as a particular culinary speciality. For a rather "smelly" mushroom they are very expensive and actually over many centuries they were mainly part of the rural cuisine, probably because of their strong aroma.
As it is the case with specialities, they suddenly become valuable only because nobody wants to eat them anymore. The truffle seekers lost their business and invented lots of fairy tales about why the truffle is allegedly so fabulous.
And because people like to believe, this same trick works the price begun rising astronomically beyond any reasonable, rational argument. This is exactly the principle by which a consumer society functions: A product is described as sensational without any real evidence, but the fact that so much attention is paid to it gives the fairy tale credibility.
So, the "speciality" suddenly becomes a profitable product and is then used by the "haute cousine", like all fashionable dishes do if their ingredients, like, intestines brain; lung, stomach etc, are having a completely unrealistically market-price.
There are still many truffle pigs around, but most truffle these days found by dogs. It took my little Rottweiler a day to understand what to detect near oak-trees for and then to exchange it for a piece of dried turkey breast. Unfortunately his strength proved to be unsuitable, - he dug the stinky mushroom out of the ground in a few minutes, but the mushroom was also destroyed by his claws.