The original point of @marcus335 comment is that Mac used to be the main revenue driver of Apple. 30 years later, Apple develops an iPhone business which replace Mac as the main revenue driver of Apple. From 2007, iPhone is a 15 years old product… still young 
No urgency for a new main revenue driver. Revenue of iPhone overtook that of Mac in 2010. So Mac has been Apple’s main revenue driver for 33 years while iPhone has only been for 12 years.
1 Like