Welcome to Beoworld !
The woofers in your Beovox S80 are not original (and they don't have foam rot).
It's safe to say that all original S80 woofers suffer from foam rot now if not repaired. Many owners are not aware that a repair is possible and buy new replacement woofers. Sadly, too often the original woofers are thrown away and the replacement woofers are of an inferior quality since the original specifications are practically impossible to match.
An upgrade for your Beovox S80 would be a pair of original refoam'ed woofers and a fresh set of new capacitors for the crossovers and no doubt, you will find the speakers sound much better.
The original drivers were designed for this cabinet, if any change in specs would have improved anything it would already have been done. Generally, in B&O speakers, the original drivers are superb and the best choice for the given cabinets.
I would imagine the same goes for B&W.
Martin