What you say about carby engines is correct if the F:A ratios are not balanced. Once they are balanced (by a knowledgeable operator using carb heat appropriately) the engine can be run quite successfully with all cylinders at the same F:A ratio and, therefore, all ROP or LOP with smooth operation.
There are many carbed engine operators doing just that.
It is important to realize that the problem is NOT one of air imbalance to the cylinders, but of inadequate fuel vaporization early in the induction system to deliver the same F:A ratios to all cylinders.