I don't suppose you have ever tried to use an oil bath filter in a truly dusty enviroment. In my case, the worst case enviroment is picking peanuts. We've had to stop and clean out the stupid oil bath filters multiple times a day and still dirt gets through. The intake between the filter and carb are coated.with oil residue and dust. With modern paper filters, no problems. I can't imagine anyone who would want to go back to oil bath filters. Even when properly maintained, they are inferior to modern paper filters, and if not properly maintained they are a disaster. They may have been state of the art 65 years ago, but their time has past.
Ed