Damascus is a mix of various steels, heat welded together and manipulated (twisted, folded, filed....) to form a pattern. The reason it is so expensive is the labor intensive manufacturing processes. Look for the many WIP's on Damascus making done on the forum to get an idea of the work involved. Because Damascus can be made of knife and non-knife suitable steels it cannot be included in a best steels thread because every batch can have different characteristics. Take a complete weld for example- blades are often folded so that there are 300+ layers in a billet. If 1/100 layers isn't completely welded the you may have a void or inclusion on that blade and have it fail at an opportune time- say when boar hunting and trying fir the killing wound. As patterns become more intricate, the workload increases, which also increases cost.
That said- I love using Damascus from good makers (damasteel, combos of: O1, 52100, L6,5160....). Hope this helps.