Those cables always seem to be insanely expensive and the hardware I have bought up to v3 (I dont have anything with v4 or v5) does not deliver on the promise

Those cables always seem to be insanely expensive and the hardware I have bought up to v3 (I dont have anything with v4 or v5) does not deliver on the promised / potential speed. (the promised speed now is far arger) This is primarly external storage. and I paid huge premium for the ThunderBolt 3 external drives to use wy Imac (or Macbook). A USB C drive I use under windows (that at least does not declare itself as Thunderbolt 3, and using a standard (to what extent that exsists) USB C cable is far faster. (and swapping in the true Thunberbolt cable does not not make it any faster)