Apple restricts its computer manufacturing line to only a few basic models that can be assembled in four minutes, which gives customers a good choice with quick delivery. This is an example of .

unsegmented marketing

Explanation:

An unsegmented marketing strategy (A.K.A. mass marketing) takes place when the producer of a good or service views their potential market as homogeneous and therefore carries out only one single marketing program to try to reach their customers. This single marketing program generally includes one (or few very similar products), one price (or very similar prices), one single promotional effort and a similar distribution system for every customer.

In this case, Apple has probably determined that most of their potential clients fall under one category, and that they value short delivery times very much. That is why their product line depth is actually pretty shallow.

This happens not only with computers, but also with iPhones and iPads. If you compare Apple's product mix length to other manufacturer like Samsung, they offer very limited variations of their different product lines.