There is much speculation about the reasons why Apple does not want to use Intel processors any more. The focus is usually on computing power and power consumption, or compatibility with iPhone and iPad apps is cited.
This CPU-centric view is certainly justified, but it only reflects a part of the "Intel architecture", because every processor has a suitable chipset. To be precise: For each chipset there are suitable processors and announcements of further processors, because the innovation cycles are here not as fast as with CPUs. The chipset is crucial for the system design, from the bus to memory and interfaces.
ARM's SoC approach offers greater freedom for the system designer, because the CPU cores can be expanded by the desired functionalities on-chip or by removing unwanted parts. For hardware manufacturers, it certainly has its appeal to integrate uniform functions such as cryptography and AI accelerators across the entire product range and thus offer software developers a uniform programming interface.
But it is also an advantage if a system provider has identified a bottleneck that can be exclusively eliminated - at least for a while - and thus has a competitive advantage. With SoC, tool chain and operating system from a single source, it is also easier to cut off old habits and introduce innovations.
At the end of the year, Sony with its Playstation 5 and Microsoft with its new Xbox will provide examples of this. Both companies are relying on AMD SoCs with the same Core (Zen-2) and GPU architectures (RDNA2). Although the SoCs are x86-based, both companies are moving away from the usual PC architecture: instead of DDR4 memory, GDDR6 is used and instead of NVME SSDs, both use custom SSD logic for more bandwidth for the graphics-intensive applications.
With its own SoC, Apple has even more possibilities for system optimization than Sony and Microsoft have demonstrated. Moreover, performance per watt can be increased not only at CPU level but also at system level.