I built a pair of small monitors in 1990 using the Audex Europa 8 co-ax driver. It has a foam rubber surround around the woofer. I've used them constantly with no problems. Most other speakers I've seen with foam surrounds don't last that long. My Grado earphone pads, SR-80, didn't even last 2 years and I hardly ever used them.
Look at the Dynaco A-25 and family. The drivers were Seas and earlier Scan-Speak. They used rubber surrounds and seem to still be around in large numbers. I would like to know what kind of foam rubber and what kind of glue was used on those drivers. If they are made in China now, not France, Norway or Denmark I would like to know.....Mark Korda