We were SOOOO COOOOL in the 1990s. Dura Ace and other road cassettes and freewheels. Ti MTBs with 105 rear mechs, XT thumbies then XTR shifters, Suntour front mechs which actually worked, Mavic Dakar hubs with spin-on freewheels. it was indeed great that everything was indeed interchangeable. Long gone openness and transferability. In comes market capture and incompatibility and a nightmare for LBS Re what stock to hold. Welcome to internet shopping from whoever has what obscure incompatible thing which you need (but don’t necessarily want). Ok, stack height on threaded headsets was a problem re switching headsets but axle standards, BB standards etc all helped to ease the openness and experimentation. I’ve adapted to having to check, check and check again, but still have had issues in recent builds re Boost/non-Boost crank requirements, and getting chainline right. I’m on top of axle spacing these days but sure have more wheels hanging in the workshop than I did BITD and it’s a PITA…