Apple has been iterating on their proprietary mobile ARM-based processors since 2010, and has gotten really good at it. I would imagine that producing billions

Apple has been iterating on their proprietary mobile ARM-based processors since 2010, and has gotten really good at it. I would imagine that producing billions of consumer devices with these chips has helped give them a lot of experience in shortened time frame. I also wonder if having the hardware and software both worked on in-house is an advantage. I mean, if you're developing power management software for a mobile OS, and you're using a 3rd-party vendor, then you read the documentation, and work with the vendor if you have questions. If it's all internal, you call them, and could make suggestions on future processor design too based on OS usage statistics and metrics.