Actually, ARM is used for serious gaming, just not on PC. In particular, many of Nintendo's handhelds use such CPUs; this includes the Game Boy Advance, the Nintendo DS, the 3DS, and even (I believe) the Nintendo Switch. (Also, the smartphones that are supposedly more powerful than the NS also tend to use ARM CPUs.)

nintendo is for kids , clearly not serious gaming
smartphone gaming is the worst thing happened to humanity
probably apple just want everything made/controlled by themselves like a cult

I appreciate everyone's inputs here.

My two cents: I agree that the market is king. While Imagination has an interesting ISA, IP, and microarchitecture design but lacks the brand power of a company like Apple. I know that Apple has kept changing architectures but this is not about Apple per se.

Microsoft too has been trying to bring ARM to windows with little success. Now, Qualcomm's acquisition of Nuvia could lead to interesting possibilities. It is the survival of the fittest.

It is a misconception that ARM cannot do gaming well. It has had a presence in consoles and imagination can do real-time- ray-tracing as well. It has in fact had real-time ray-tracing capabilities for a while now. In fact, it demonstrated real time ray tracing well before nvidia claimed that it was re-inventing the wheel. I'd argue that a system on chip approach with a unified memory architecture is a better and more efficient approach for mobile gaming. It's very different from having an IGP.

I have been a pc gamer forever and would hate to see legacy support go. However, having a powerful and highly power-efficient mobile device that runs windows is something that I look forward to. If it comes from AMD/Intel then I'd happier than a pig in a slop. However, I don't see that happening unless a full-fledged system on chip approach is embraced.

In the end, the market is king. Let's wait and watch.