That is very true, you can natively play GC games on the WiiU with a little modding. But Nintendo can't make money off that. It's either re-releasing old GC games as newer HD cashcows like WW and TP or you virtualise them so people can pay yet again to play them virtualised on the NX.Or maybe they just never got around to it? Or why bother repackaging games when the popular ones could simply be cleaned up and re-released for more money? *ahem*Windwaker*ahem*
Remember that the Wii was just a beefed up gamecube. Anything that could run a wii game could run a gamecube game.
Oh, here's a reddit thread where people are discussing it:
https://www.reddit.com/r/wiiu/comments/2r7mdc/so_why_cant_the_wii_u_play_gamecube_games/
In a nutshell, the WiiU can be modded to play gamecube, no emulation required.
Nintendo did get lazy on natively playing GC games on the WiiU. But since the NX seems to have different internals, the GC games will have to be emulated on it.