rome2807

Apple's strategy has been vertical integration by controlling all key aspects of the software and hardware stack. This isn't possible with CPUs that have to be designed with all eventual use cases in mind. Product cycles (initial planning to rollout) are extremely long, leaving Apple with little control over the end product. Reversing this must have been a strong incentive to Apple when making the final decision to take this inhouse.

Getting there took Apple many years of due diligence, prototypes and validation. It is not going to be reversed on the grounds of potential faster CPUs / more power-efficient CPUs if control has to be sacrificed for good. And this scenario would not materialize unless Intel executes on their claims of regaining process leadership. If they do, Apple could easily adopt Intel's foundry service, resulting in a much more probable win / win for both companies. Intel's Foundry services are open to competing architectures such as ARM and RISC V even today.

Re: "The device packs 32GB of 1333MHz DDR4 memory. Although that may sound improbable, current iMac devices released in 2019 clock in with the same RAM frequency. "

The clue is in the different represenation. 1333MHz is the underlying clock rate of DDR4-2666 RAM which in turn has a transfer rate of 2666.67 MT/s . So Apple reports the transfer rate with the right number (rounded) but the wrong unit of measure. Geekbench reports the underlying clock rate which is 50% of the transfere rate number). See https://en.wikipedia.org/wiki/DDR4_SDRAM for a table with corresponding values:

From Apple system report - 

...

BANK 0/ChannelA-DIMM0: [ of a total of four ]

...

  Size: 16 GB

  Type: DDR4

  Speed: 2667 MHz

  Status: OK

  Manufacturer: Micron