I think portability is dramatically overrated.
When exactly is it useful?
During school/work? Certainly not.
When you're at home? No advantage over a console/PC.
On the way to school/work? Only if you use trains/busses (and longer than say 10 minutes per ride).
Is anyone going outside just to play with a handheld? Even then a laptop/tablet would suffice.
And don't get me wrong, 4k is just a bonus.