The problems with rubber are twofold.
The first is aging-- they simply get old and crack. Exposure to oxygen and sunlight causes rubber to fall apart.
The second is oil and other petro-based chemicals. Exposure to petro-chemicals also kills rubber.
I once had control over a fleet of Ford wreckers with Twin I Beam Suspensions. This suspension system was great for pick-up trucks but lousy for wreckers. I converted some to straight axle front suspensions but it was a big job and the necessary parts were all used and getting hard to find. (And usually in need of kingpin bushings.) These trucks were old, always had a few leaks, were too often overloaded, operated 24/7 and needed new control arm bushings about every 2 months. I eventually found neoprene bushings that were guaranteed for life. The cost was about 10 times the cost of the rubber bushings but I stuck my neck out and replaced every one in the fleet with the neoprene bushings. The stock rubber bushings weren't very expensive but it took a couple of hours per truck to replace them.
Of course, the boss went nuts when he learned what I had just paid for new bushings but 3 years later he was telling all his buddies in the wrecker biz how he had solved his bushing problem forever.
Now if we could find someone willing to make neoprene bushings for our XSs....