Then again Bert, what about the cost of Fruils or other metal track links? Those can be more than the actual kit cost, not just a chunk of it.
People spend a lot on aluminium barrels, tracks, etch sets, decals, etc, so a set of resin wheels is all relative. You don’t have to have them if you do not want them, but often they, especially DEF ones, are so much better that they are a very noticeable improvement over the kit offerings.