Unfortunately it's an oft-repeated complaint about O scale. It would be easier to stomach some of the high prices if the quality matched, but somehow the old attitude in Britain that "It's O scale so it must be expensive" seems to be applied regardless. More a case of "What price can we get away with charging?" than "What price is this really worth?".
Another thing irks me about that sort of kit, just from looking at the box lid; okay - leave choice of wheels and coupler to the buyer (itself a bit of an out-dated notion, now, I think?), but no Transfers...???? Slaters do the same... to my mind it means the kit seems "incomplete", and also opens up a whole minefield of what transfers to get (assuming any are available) and their accuracy for the model.
All I know is, I hope no wagon experts ever check out the numbers on most of my wagon fleet ...
Wagons... schwagons....
Sorry, Rant Mode OFF.