I can take my time, wind and build ten motors, be as careful as I can doing them all the same, use the same basic components, do the same assembly... and wind up with noticeable variations (on the power supply anyway) between them.
I'd just like to inject a little dispassionate reality into the whole question around these things. Now, take that same premise, but apply it to a batch of maybe (?) a hundred thousand or so motors mass-produced to meet a low price point, and I find it shocking that the variations aren't huge!
Actually, the fact that some will buy a whole bunch of the "FK" Chinese motors to find one or two cherries only underscores how consistent (generally-speaking) the motors are.