My problem with this take is that it takes ARM > x86 as some kind of given, like there is an inherent flaw with the x6-64 ISA that means a chip that provides it can never be competitive with ARM on power consumption.

We've already seen Intel and AMD narrow the gap considerably, in part by adopting designs pioneered by ARM manufacturers like hybrid big-little cores.

Another aspect that I think gets forgotton in the Steam Deck conversation is the fact that AMD graphics performance is well ahead of Qualcomm, and that is extremely important for a gaming device. I'm willing to bet that the next Steam Deck goes with another custom AMD chip, but the generation after that is more of a question mark.

RISC-V is another wildcard that could end up threatening ARM's path to total dominance.