I get what you are saying about power and energy. That isn’t really what I am arguing.
I am curious if that energy we are talking about, the one that is being converted to heat in the shock/fork would otherwise turn the cranks. My gut feeling says locked out is more efficient too, but I find that lately a lot of the conventional wisdom as it relates to cycling, have been false:
- flat pedals versus clipless: Actually not more efficient
- crank lengths
- skinny tires
- high pressure in tires
- and so on
I think this would be an interesting, low tech test, that could offer some insight:
Put a rigid bike onto a trainer. Place a scale under the front wheel. Place a scale under the trainer.
See if the weight (contact force) changes as a cyclist is cycling.
If it does change, that should imply force/energy is being “wasted”, and would have compressed the suspension.