But it really isn't expensive any longer - if you look at the 4mm (& some 2mm loco's) the prices are becoming much more levelled.
Yes my comment was a bit tongue in cheek - the prevailing viewpoint of "it's O Scale so it
must be expensive" has certainly been challenged especially by Dapol & Minerva as far as R-T-R goes, and yes in the meantime prices of OO & N (which are often the same for equivalent models) have risen.
The other main thrust of my comment was to do with the oft-repeated delusion that most of us entertain when starting a new scale or project - "I only need one loco & a handful of wagons".... yeah right
I said that myself when getting into American O Scale. About a decade or so later, and about 15 locos and over 50 freight cars later as well..... definitely blew that presumption out of the water....