My, I can't even begin here. For starters, we're talking about something coming 3 years from now. Today's technology being irrelevant. A system like the switch could have released last month while already being more powerful than a ps4. And no, the gap between the switch and ps4 isn't 3-4x, more like 2-2.25.
Even in 5 years that won't be possible without having less than 1 hour of battery life or a handheld that weights a ton. Maybe by 2028 or so they could do so effectively, but with Moore's Law looming ahead, I have my doubts.
Also, Nintendo by far and large prefers using proven technology rather than the newest non-plus-ultra bleeding edge tech. In 3 years Nintendo will be using today's technology as far as computing hardware goes.
Switch can reach about 400 GFlops docked and 240 GFlops undocked. Even just the XBO S is over 3x in terms of raw performance compared to docked Switch, PS4 even almost 5x as powerful. Even the beefiest Smartphone chips can't reach that yet, Snapdragon 855+ stands at around 1000 GFlops - and if you game on those something that fully uses the power, either their battery is sucked empty in short notice or the chips are downclocked to save battery, at cost of lowered performance.
Finally, despite the rather weak performance compared to the consoles, the main gripe players had was not performance, but battery life. Hence why Nintendo used the new chip from NVidia not to enhance performance, but battery life.
In short, if by 2024 a successor to the Switch will come out (I don't expect one earlier unless Switch sales start to tank like those of the Wii) and will still be a hybrid console like the Switch, it will probably be much closer to XBO S performance and not come anywhere near XBO X.
The Nintendo eShop rating Thread: http://gamrconnect.vgchartz.com/thread.php?id=237454