I had a friends brothers cousins girfriend that worked with a guy that knew somebody whos dog saw bigfoot once.

OK. They obviously are not exploding under riders on a regular basis. If YOUR frame failed, post up. Let's see how many there really are. Frames of any material can fail due to a myriad of reasons. Most are probably due to reasons other than material fatigue. My 7 year old Al GT MTB is holding up just fine. I have been in the air more than a few times at over, I'm ashamed to say, 200 lbs and it is fine.