I think the problem is that Apple themselves want to reinvent and innovate the heck out of everything all the time, so they're making it harder than it needs to be. New Mac Mini? Easy: spec bump the current form factor. New Mac Pro? Easy: put the latest and greatest CPU/GPU in the old cheese-grater enclosure. But no, Apple needs to contantly make everything smaller/thinner/lighter/quieter, so they redesign the enclosure and reengineer the internals from scratch. While they're busy doing this, they continue to sell the old unimproved products for years.
Yes, Apple, we know you can innovate. But you say that for every "yes" there are a thousand "nos". Have you considered saying "no" to a complete reinvention of your hardware when your current offerings are so out-of-date? Your customers would be happy with a spec bump of the current form factors.