First of all, many flutes that are marketed or even engraved "professional" are still made on an assembly line, with many parts stamped out or totally machine made (even CAD). They in no way compare to those that are at least assembled and padded, regulated etc. by one master craftsman at their own bench. ( Yes, some pro parts must be machine made.) Yes, there is an enormous difference. Do you ever see a top pro endorsing one? Sure - sometimes, they really believe in that instrument, and it is clear to ALL other pros what level they are really selling to - and sometimes it is just a money thing, like endorsements in all industries. And those TRUE high end instruments are never stamped/engraved "professional" - they are just made by craftsman who only make instruments at that level. Most band kids would not even recognize the name. If you read at a fine makers website. like Muramatsu, each step will be explained, and possibly broken down in hours. But there is no time clock - quality is more important that time. This is not much different than the amateurs here who ask "How long will it take me to learn to play the Ibert Flute Concerto? I just started flute in Band 2 years ago." Gonna take a while sweetie.