I think you are right. Look at the poor sales of the Peco Collett because people did not want to pay an extra £30 for the inbuilt decoder.
I happily payed £130.00 for a Peco Collett because my only other options in N gauge would be a less detailed kit or a very time consuming scratch build.
It is not profitable for a manufacture to do something to keep 10% happy and these days manufactures, model clubs, shops and at expeditions modelers are being encouraged to move to DCC for the benefits, as posted before "two LEDs feeding a single light guide" will work wonders for DC this is only my opinion but Dapol are experts at preventing light bleed so no problem there.
having been to many model clubs and experience with different types of DC and DCC I am sure that some thing like that would sell
Also did you know That the forthcoming BR western class 52 by Dapol will be the most accurate model ever due to the real thing being (LASER SCANNED) which took two days to completely scan the whole thing this is expensive to do and will be expensive to produce but if they go on the shelves at £95.00+ I'm sure they are guaranteed to sell because they will accurate and there will be no need for modelers to buy extra parts to correct it,
I think some people will move from 00 Gauge to N just like what happened with the class 67 the Dapol version is superior to Lima, Hornby and Kits and look at the quality of detail then look at the scale difference, ok the price of the Dapol version is higher but for what you get it is well worth it, The only negetive I can remember was i a magazine review when it was stated that the light clusters look slightly over scale, in my case thats at an acceptable level can you get an of the shelf 00 Gauge class 67 with working top light no but in N gauge the answer is yes
The main point is if I spend an extra £40.00+
I will NOT need to buy etched name plates
I will NOT need to buy grills
I will NOT need to buy extra paints
I will NOT need to buy transfers
I will NOT need to buy lights and wiring