Irises became fewer bladed in the 1950's for some brands. It's interesting to see cameras like expensive 1960's collectible Rolleiflexes have fewer aperture blades than older automat versions but I don't think they make as nice a photo all other things being equal. I think it was a subjective thing that costs happened to favor. If you look for LF lenses and want a smooth round iris and lens coating, look for a generation post-WWII. Not too new.... Later Copal-3 and 3s seem to have a pretty close to round iris but don't meet the small requirements. It's a small subset of available lenses. 35mm camera companies are fully onboard with making super round irises now. Sigma art lenses are this way and the newer Nikon high end lenses all brag about the blade quantities and smoothness. Until recently you could tell if a photo was Nikon or Canon from counting the sides in a bokeh hotspot or sunburst. There is no real overwhelming need for new LF shutters until used ones are no longer operable. It would be a tough sell.