As an actual homebrew developer; I can give you some valid reasons. First, however, I'd like to point out the Chip8 emulator and the GameBoy emulator, both of which have been out for months. Go give their devs some love.
- A complete and utter lack of community support. "the wii u is dead; all the devs are useless; there's no homebrew; just move on" right before someone prints some colours to a screen and you're all over that for months, while I'm just left to my own devices in the background. You start to believe the stuff you're told, y'know. It's finally starting to collectively sink in to homebrewers, have you noticed it?
- The Wii U is a pain. That's why I love it. However, combined with point 1 it doesn't make for a compelling development system.
- The Exploit Shitshow. I hinted at this in point 1, but all this IOSU stuff is actually really annoying and we should all stop acting like its release will magically make all your dreams come true while simultaneously ignoring the dreams that have already been released. The devs keeping stuff private are only fuelling this fire. I understand there's a development cycle and a brick risk (and SALT is handling this excellently) but someone needs to change PR strategy, and the community sure isn't.
- The forum. There's a link in my signature to my attempt to fix this.
- Motivation/lack of interest/whatever. Partially my own fault, but also caused by the other points in combination.
- Sleep deprivation/possible depression. Completely my own fault. I'm working on it.
I'm no speaking for anyone else here, but I suspect they have similar issues too (maybe not that last one). Well, I hope that gives you some "valid" reasons; and hopefully you can realise that it's a number of factors contributing to stagnant development rather than being lazy.
As for the OP, I'm sure it's possible, but who cares? The Wii U is dead, after all. You'll all get your prized IOSU exploit, but you'll have alienated everyone you need to make it useful in the process. Seriously, can we just
stop?