Doesnt that have a lot to do with region? I ask because I worked all over Europe and N. America during my chef days and I can definitely tell you that my stint in Croatia made me realize that truffles are not that highly regarded--I saw black ones thinly sliced on slices of $1.50 pizza slices at the bakery during the heavy season--when they are plentiful, and the oil was entirely non-existant. What wasn't used was canned and labeled a delicacy next to the little spreadable ham things that sold for like 80 cents back then.
While when I was in Italy you rarely saw them on menus outside of 100+ euro a menu places and typically only in season--I worked in mainly farm to tables is in the Emilia Romanga area so we got lots of parama ingredients all year round but truffles were a special occasion kind of affair that was limited to maybe 3 weeks or a so a year.
In London I just took it for granted that this was a marketing ploy to get the people in the city to justify the wildly expensive outings a reservation/menu cost, and in Cornwall they didn't even care about them at all. Germany, and Switzerland were pretty much the same.
I didn't have truffle oil until I got back to the US, and it was used for innocuous things like fries in a steak frites entree.