Nah much sooner than that.
It’s coming later this year or early next year.
The revision will be using a custom X2 chip.
2020 will be Switch 2. Using Xavier which will put on par with Xbox one X and 8K video rendering. One thing to keep in mind is that arm is catching to x86 very quickly.
Apple is already will be ditching intel chips which will further innovate mobile chips.
Custom X2 Chip for the revision is the only possible thing here.
1. There's no reason or even possibility (development takes time) that it will launch before holiday season 2019 earliest.
2. ARM is nowhere catching up to x86 chips. What changed was the max TDP got raised from ~5W to around 30W for small servers and for autonomous driving cars. Of course with 6 times more headroom the performance skyrockets, but from an architectural standpoint X86-64 is simply miles above and away over ARMv8.x.
3.Apple is switching to ARM to have an unified ecosystem, not because ARM would be catching up in performance, which it doesn't. Well, they are very slowly catching up to the Macbook Air models, but those have been extremely weak for the last 3-4 Generations, yet still ARM doesn't come close in performance as of now. The only advantage the ARM cores have in terms of performance is that you can cluster more of them together in such a small hardware, but that doesn't suffice to beat x86