On the customer side of a business though, marketing managers love offering something to every segment of the market. All the offerings on the market side are called "assortment." Businesses start a new product line based on good market prospects. The distribution side then builds up with more dealers,more marketing and service support,service training,aftermarket spare parts and so on. Unfortunately, there is no manager standing in the showroom end and looking backward at all this "complexity" - at the showroom managers are happily showing the assortment to prospects !
Closing product lines or product deletion is a complex activity, that does not bring glory to the marketing manager. Consequently, it does'nt get done till there is a crisis as currently, as in US Auto.