The sun's ultra-violet rays -vs- BMW's decades old commitment to the use of recyclable materials so as not to fill up mother earth with the dead carcasses of our past motoring marvels once they've outlived their usefulness. The deterioration we see of rubber trim & the use of exterior & interior plastic trim stems from BMW's commitment to green ecology that is decades old.
Having been around prior to BMW's adoption of green ecology (having owned a BMW in the 80s, and had friends that owned BMWs in that decade, too) I was appalled when the e36 3 series debut. The interiors looked and felt really "cheap" compared to the e21 & e30 3 series that preceded them. And everytime I read (and see) trim failure as is mentioned in this thread...I'm always reminded of this turn in BMWs history that some may not be aware of as to the "how & why" these things occur on BMWs.
Excerpts from an article published:2/21/1993
Ecology: Where cars will go when they die: BMW is stressing the recyclability of its models, looking to the day owners will have to pay for their disposal:
BMW is particularly keen to establish itself as a maker of green cars. As a producer of often high-powered, flashy machines, it has become the target of environmentalists. The idea of the recyclable car is one of its the ways it is fighting back. Its advertisements for the new 3 Series stress that a significant proportion of its parts can be recycled. Landshut is part of the same effort.
With its latest 3 Series car BMW manages to recycle over more than 40 per cent of the non-metal components, which make up a quarter of most cars. These plastics and rubbers are the problem materials, not the metal which has traditionally been recycled by the steel industry. The aim is to get as quickly as possible to near- 100 per cent recyclability.