It's just luck and you happened have a bit of bad luck. I picked up a used Mac mini 1.83GHz about a year and a half ago and it's been running 24/7 without problems. I even ripped it apart and upgraded it with a 2.33GHz CPU.
On the other hand,I've also had equipment that died after very little use (a particular HP printer resounds in my mind)... It's just luck...
On the other hand,I've also had equipment that died after very little use (a particular HP printer resounds in my mind)... It's just luck...