I think the Apple leadership's thinking is as follows: - The revenues and market share of Apple's Mac unit has been stable for years[1]. No big gain, declines

I think the Apple leadership's thinking is as follows: - The revenues and market share of Apple's Mac unit has been stable for years[1]. No big gain, declines or spikes, regardless of how frequently they update, or how close their hardware is to the bleeding edge. Therefore, it makes sense to reduce their expenditure on the Mac until they see a drop in either revenue, market share or profit share, or some other genuine sign of danger beyond the griping of some professionals. - The personal computer market overall is declining. Spending more for a slightly bigger slice of a shrinking pie isn't worth it, because there's no real opportunity for long-term growth that will please shareholders and analysts. - Reducing the cadence of Mac hardware updates gradually closes the gap between the performance profiles of the iOS and macOS hardware, which moves them closer to the eventual goal of unifying the mobile and desktop software market. - More frequent and more regular updates give more power to Apple's suppliers, as they become dependent on them for the components necessary to provide the updates expected by the market. Supply change management is Cook's area of expertise, and by delaying Mac hardware updates, and doing them on an irregular schedule, Apple can reduce supplier leverage, and walk away from deals it considers to be too expensive. The most important supplier is, of course, Intel, and I think Apple would love to break the industry out of the idea that the supplier tail wags the dog in terms of CPU adoption. E.g. Intel can't just produce a new microarchitecture on their own schedule and assume all manufacturers will rush to adopt it, but instead have to accept a somewhat more subordinate role, whereby the big vendors like Apple can say "this is what we want, this is when we want it, and this is what we'll pay for it." [1] https://www.macrumors.com/2017/11/02/earnings-4q-2017/ https://www.macrumors.com/2017/11/02/earnings-4q-2017/