Apple utterly dominates the mobile phone CPU landscape, and it’s hard to see that changing. The reason is that they capture a huge slice of the profits in mobile phones. Something like 90%. For a while they capture over 100% of profits, because so many of their competitors were operating at a loss. This enables them to make investments their competitors can’t. Also because their competitors use commodity chips developed by Cisco and Samsung none of the Android vendors can use those chips to differentiate their products, which means even for flagship phones the CPU isn’t a unique selling points, so they can’t justify buying super premium chips. Without the guaranteed sales, the chip vendors can’t justify investing in making super premium chips. They’ve been stuck in this rut for almost a decade now, and still not found a way out. Success breeds investment, but without investment they can’t achieve success. It’s a negative feedback loop, compounded by a prisoner’s dilemma.
With desktop and server chips these factors don’t apply. Apple will never dominate the desktop and server CPU market because they’ve positioned themselves as a niche premium brand. They don’t even make servers, and the desktops they do make are ridiculously high end. They can’t go down market without eviscerating their margins. There’s still huge amounts of money to be made in those sectors, so vendors like Intel and AMD can afford to put in massive investment in new designs. They may be behind now, in some ways, but I don’t see any barriers to them competing in the near to long term.