It helps if you understand how mainstream product is manufactured.
A company like Monitor Audio will design a product and then decide how many they are going to sell, the marketing guys will have a big say in this.
With this decided, they can order in the parts and materials needed for this production run and allocate time on the production line. This will determine the factory price of the product and keep it as low as possible. The production run will be completed in it's entirety with the sales people simply required to sell the product at a profit.
If the product is successful and sells well, there is a bit of a problem. The production run can not be extended as the stock of parts has been used up, they will no longer be available at the original prices, particularly if the numbers are smaller and in some cases may not be available at all.
This is understood so they move to the next product, which will be a Mk2, SE improved model if the first was successful or a 'brand new' design with a different name if it was not. The designers may have looked to improve the product but this is just one, relatively small part in the whole production cycle.