Re:
XTR was the top OEM Shimano groupset (brakes, levers, shifters, chainset etc) of the time, and was too expensive to fit to many retail bikes, so was limited to small runs of the very top models in each manufacturers’ range. Basically they were ‘money no object’ show bikes, with very few assembled and sold. The main appearance of the groupset was in racing, as a showcase for Shimano engineering - like Mercedes and Audi participating in F1 and sports car racing. Individual parts and occasionally the whole groupset was bought by small boutique fabricators for bespoke builds or to individual people doing top range personal builds. The next groupset down, XT, was much much more common, and carried much of the same quality peformance, but without the Rolls Royce feel and appearance of XTR.