I'd guess more due to them being one trick ponies.
And for the most part, the one's that aren't one trick ponies are much less intense.
I know that TTD and Kinga Ka have had their difficulties, but have any of the other Intamin rockets had any other significant downtime beyond the first month or so of operation?
I know Speed Monster had it's problem when we were out there, and Stealth was down for a week or so, but really, I never hear of any problems with XLR8R, Storm Runner, Rita, Superman, Kanonen, or even Stealth or Speed Monster beyond the short down time this summer.
I really only think the reliability issue is with the "world record breakers."
--Robb
Stealth was down for more like 6 weeks last season in one go, not to mention other days where it just failed to run. Rita on the other hand had a few days here and there, but nothing extended. Overall, Rita had an arguably good season. She's still not in the top 100 though.