I'd kind of guess today's carbs are also better and less restrictive than they used to be. That might make a difference in whether or not it's worthwhile to replace the carb with a venturi on a given engine.
I have an OS Max .30 RC engine that is a mild easy handling engine that doesn't match my surviving Fox .19 baffle engine on a 9-4 prop for power, let alone a .25 Schnurle. However, a few years ago, for SAM competition, I pulled the RC carb and turned a 0.200 venturi, and used an old thin Kap-Pak needle assembly. The engine went from about 11000 max to over 14600 on 10% fuel.