I think Sheldon Brown showed how most drag, or rolling resistance, is caused by the energy ‘absorbed’* by the tyre deforming when it rolls beneath the wheel.
You can reduce how much energy is absorbed by either pumping the tyre up harder, so it deforms less, or by reducing the amount of rubber being deformed, say, by removing the inner tube.
I can’t prove or disprove this, but it works for me. I’m running under 30psi instead of over 35psi, yet the tyres roll just as fast (and feel faster over rough ground).
The tyres don’t wallow in corners, in fact, the bike seems to spring out of the corners faster than it went in.
And I’ve bashed my rims a few times now with no obvious dings, certainly no more than when i was running tubes.
*Or something, you know what i mean