Speaker brands with rotting foams?

this isn't a brand issue, many/most brands have speakers that use foam surround drivers. It's a design choice.

Most of the speakers from the 80's and before had surrounds that could rot. Usually lasted 10 to 20 years and not a big deal to get repaired. There were some excellent and unique speakers from that era that were a bargain, compared to now. Granted, Mission 700's might not be worth the expense, but Infinity RS1b's ...

some of the foam one sees on modern drivers is made of rubber like fostex f200a

Wilson speakers used foam until the most recent models. Whoever has the older versions have to pay big money every few years. Even the foam on the cabinet front needs to be changed! Wilson should charge less for the maintenence.

Advent Loudspeakers from the late 70's & 80's. I've refoamed mine twice and will keep doing it since they are still fun and sound good when stacked in parallel (I have 10 of these cuz I bought or took them back from all the people that bought them on my rec over the years).