With rumours of PS4K or PS4 Neo, and an upgraded Xbox One, should Nintendo think about joining this new game console trend? And if they do, should they take advantage of joining in late by making the NX able to upgrade itself like a PC? In other words, the upcoming NX home console release will have the ability to not stay outdated if you buy another device thats cheaper than an entirely new NX but is able to make it run like a new upgraded system. Or would it be a simpler and better business decision for Nintendo to make the NX like the Gameboy and 3DS, requiring a new system when updated? 

The other question to be considered is if the NX needs an upgrade depending on how long PS4K/Xbox One+ stay on the market. 

Nope.. didn't work in the past.. no reason it would work nowadays

from the looks of things it will have the ability to attach additional components to give it more power. im guessing after the NX has been around for say 2 or 3 years and Microsoft and Sony roll out their new consoles, they will just release an add-on to have the NX stay in line with the competition

We also never seen a new independent, upgraded hardware sell next to its original in just 3 years as well.

Yes, choice is a good thing

I honestly don't know why some people have an issue with choice. As long as all games work on all variants, I don't see the problem

3DS & N3DS is i think in 3 years.. and before that Gameboy & gameboy Color and DS & DSi but they had more time between them... I  think Nintendo would follow that route again with an updated NX+

I don't think they have a choice.

2.4 TFLOP console NX with the option of a supplemental GPU add-on is the only way they'll be competitive in this console cycle now that Sony has thrown down the gauntlet unless they have some kind of controller miracle again. Which I doubt they do. 

I was speaking more of the expensive home consoles

I would be against buying upgrades since that means I would have to spend more money just for the hardware..

though I'm not completely against the idea

That'll be stupid. People buy consoles because they don't need to worry about upgrades.