Is it? Ever thought about the cost of putting something like that on? Yes, it is expensive compared to standing for free on a moor in the freezing cold, but there you don't have venue hire, logistics, the cost of the sections, the same levels of insurance etc etc.
If it was "stupidly expensive" then Sheffield wouldn't be a sell-out year after year - which it is. Personally, I don't see it as "real" Trials but then my introduction to the sport was the SSDT so I'm kinda biased, but it does bring Trials to the masses and can only be good for the sport.