"... who uses comparable drivers".
How do we know they are "comparable"? Maybe his drivers are better than standard versions...
It’s not entirely impossible Fritz has as special order line made to spec for his particular drivers - on some models. Dynaudio and others were doing this for years with Totem and other manufacturers starting out with custom quality wound voice coils, better magnets, or surrounds, and different baskets in special circumstances for some "signature" models requested by the builder. I’d bet the cost of the Be tweeter alone used in his Carerras is more than what some may have guessed until looking closer.
Not saying this is the case with Fritz for his tweeters or woofers. It could be though...However, as you mentioned its easy for "armchair" folks to make assumptions on the cost of the drivers, or get one digit off on a model number on a part and not realize when higher grade version drivers and components are used by a builder in a particular speaker. As already mentioned, same goes for internal crossover parts people never see, not fully understanding true cost of what’s on the inside.