I don't think there is anything wrong about EPDM for a roof. It's a synthetic rubber compound that is used in buildings all the time, particularly in low slope applications and is highly UV resistant. EPDM itself has a life expectancy of up to 50 years and is warrantied from 10 years up to as long as 40 years (in buildings).
If it doesn't last on an RV, it may be something to do with penetrations and caulking, sealing around the perimeter, the roof decking it's on, etc. I doubt they have to meet any industry standard for roof materials or installation. Like a lot of other things, I suspect it is the thinnest, lightest and cheapest which is the problem. It apparently will weather away and become thinner with time. Maybe the caulking material is not the best it could be either.
Aluminum may be a good idea, but maybe it would help if RV manufacturers just used better materials and methods of installation for other roofing types.