Well, I can explain the latter.
Each Virtual Console game is run on its own emulator which is fine tuned so the game works perfectly on the hardware.
As such, for a game to be on the Wii U, it has to be recoded with the emulator recoded so they have to do some work to do it and I guess they still want to be paid for the work so it's not just a drain in their financials.
I agree it shouldn't exist and that Virtual Console games should be cheaper (just by like £1...let's not get ridiculous and turn into the iOS argument "lolz it should be 99p"), but I can see why it does exist.