Yeah the a57 cores are used as efficiency cores in older phones, and Nintendo chose them to prioritize battery life at the expense of performance. If the rumors are to be believed they're going to go nvidia/arm again since AMD's proposed solution was less efficient at low power (handheld mode).
According to some credible leaks Sony is going with AMD for the next gen. Maybe Microsoft but I honestly don’t believe they are capable of being able to deliver consumer products on ARM. Maybe next next gen?
That would break compatibility and optimizations made for AMDs architectures, so I kinda doubt it. Unless Nvidia somehow pulls massively ahead of AMD while at the same time giving MS and Sony a better deal that is.