Kind of Sort of.....
There are devices out there where you have to jump through extreme hoops to root, and some where the bootloaders remain locked to this day.
I say kind of sort of, because at the end of the day, Android on Mobile devices (Phones, Tablets) all run on similar hardware, so the kernels are typically the same (with differences here and there).
So these hard to root device, usually have a temp root, or fastboot/ ADB pain in the ass work around.
I assume Nintendo's device would be unique enough to were you just cant throw towel root on there and open it up. Im not familiar with how the Shield is, and if it can be rooted, but it may be similar.
Of course the scene will be heavy on finding a way to root the NX, but Im sure Nintendo would have security in place, and maybe update the games to try and stay in front of them.
Pretty much if you want to this of how Androids work, just imagine you are talking about Linux (because you pretty much are). Where I work, we use Red Hat on lots of servers, do you think companies are worry because Ubuntu is so easy to modify? Same thing