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I'm hoping at least 2024. Not so much because I don't want to buy new hardware, but rather because Nintendo is kind of stuck between generations.
They need to start eating away at that and try to realign their launches close to Sony and Microsoft.
I expect by 2024 the portable mode should be capable of doing PS4 pro specs and have a decent battery. It will also give them time to work on the cradle/dock whatever you want to call it, to be able to host additional power in it to boost it significantly in docked mode. Docked mode will need to be within a couple tflops of the next gen home console in order to get simultaneous releases.
Then eventually after two more gens or so Nintendo should have been able to catch up for docked mode in terms of power and handheld mode to be perhaps 75% of previous gen's console ability.
