I've seen a video of the rega factory nearby to monitor audio in Rayleigh, and as with people like pmc, it's mainly an assembly job. Just the same with lots of hi fi audiophile manufacturers I know. They just put it together. Some like b and w have quite complicated machining processes where speakers are more elaborate.
but this description by Daved does sound somewhat rudimentary. I doubt anyone knows how many will sell, that will come down to time and experience of what is selling in the dealers etc. No manufacturer would then make a whole range in one go, not even the likes of the big electronics manufacturers.
Im sure this non 'just in time' model works for big companies like Sony with huge marketing budgets where they can be assured of sales on the back of the companies huge reputation, distribution capability, marketing spend, and can benefit the economies of scale they need to keep unit costs very low, but I doubt it with monitor audio. Also Sony etc need the tooling, and investment in same so to make a production run they would need to make it large. But most speaker manufacture aside from complicated designs like some of the b and w speakers, just require simple production and assembly that can be made more in time. There is absolutely no need to make in one go. A manufacturer will know what has sold in the past and based on their marketing they can agree appropriate unit prices from suppliers in advance, and set agreements on unit price dependent upon how the units sell and volume, at the end of the line of the speaker model.