They have it--it's called cylinder deactivation
I'm familiar with hit and miss engines. I have a 1927 IHC Type M I'm restoring in the garage (which, technically, is throttle governed not hit and miss, but similar style).
The hit and miss concept was for the purpose of governing speed, not for efficiency. Which, by the way was absolutely awful in those days--as was power density. My IHC weighs ~400 lbs and is only 1.5 hp. It's compression ratio is 3.5 to 1. That should tell you something about the efficiency.