1. I appreciate what you're saying, but you've not actually addressed the point I raised. To reverse your anecdote, if the Hornby Peckett hadn't been as good as it was, and had therefore not sold as well, it could still have potentially made more profit that it actually did if the reason for it not being as good a model was the reduced costs involved. This sort of thing gives rise to circular reasoning either pro or anti if no one actually has a grasp of the actual figures involved. Let's face it, we're assuming that Hornby are making a profit on the Peckett...
As a similarly anecdotal response (because I can't verify all the facts), I'll offer you the example of New Order's 12" Single release of 'Blue Monday'. At the time, and quite possibly still, the biggest selling 12" vinyl single in UK recording history. Because it was apparently issued to promote the album it came from and wasn't going to be made available in a 7" edit, Tony Wilson (head of Factory Records) pushed the boat out on a complicated and/or expensive picture sleeve. I do not know the exact details, but when all the costs were calculated, Factory Records made a loss on each copy sold. Like with most things, there's probably more to this than a simple anecdote can cover, but it certainly offers an example of where selling more does not necessarily increase profit. There is apparently a similar story attached to the selling of the distribution rights of the file "My Big Fat Greek Wedding".
2. You've not actually 'shown your workings' here. My highlights show the possible irony of inexactitude in a discussion about improving modelling standards.
3. I think @Chris M 's response above is better and more relevant than anything I could offer. But it seems to me that what you are essentially arguing is that if we throw enough time and money and expertise at the issue of pre-production errors in RTR models, we can eliminate the errors, sell/buy more models, and create a virtuous circle where the increasing profitability of each model feeds back in more space/time/money/skill to develop the next model. What people with some degree of personal understanding of one or other area of the whole process of bringing a product to market appear to be saying is that it's not quite as simple as that.