Apple is always accused, especially in professional environments, of not sharing its roadmaps which means that it is difficult to organize future investments. With a small change in the name of their equipment, which, on the other hand, does not help too much, now makes it easier to plan these investments.
Apparently Apple is withdrawing the references Early, Mid and Late to identify their models of computers, going on to be simply model and year. These references were used to differentiate computer models when launching several generations of the same during the same year, but with this withdrawal, it is quite clear that the Cupertino company only intends to release one update a year, at most, identifying each computer by the year model.
So if, above all, you work in a professional environment where you need to foresee the change of equipment over time, if Apple launches for example an iMac 2017 and you are waiting for an update on that model because its features do not convince you or do not comply with your expectations, you can already have an idea of when will the next generation come out: as soon as following year (or perhaps, later), but not during that same year.