Bicycles do not require extreme tolerance precision in order to work just fine. The potential wattage loss in most cases is so minimal that even an expert rider would not be able to tell the difference, or see it in overall performance.
If your cranks spins easily, your chain is properly adjusted and lubricated, and your wheels spin effortlessly, you're good to go.
I've worked with high precision tolerances with other sports in racing situations where such exactitude is critical to winning or losing; bikes don't even come close unless perhaps at the professional racing/TT level.
As a side note, my Canyon Endurace CF is the only 'modern' bike in the collection, and right out of the box it's as fast (or faster) than any of the vintage bikes that get doted over. So, there's that.
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