no, buying anything is somewhat a risk.
game delays happen. Nintendo is generally awesome at releasing games when they say they will.
Wii U gamers can still buy the game for the Wii U OR they can upgrade to an NX. its their decision. the option is there. its absurd to expect Nintendo to give out free copies of a game as some sort of reward for someone buying their new system when they are offering the game on BOTH systems
if Nintendo had originally said "the game will be on the Wii U" and then it ended up ONLY on the NX that would be different, but Wii U fans can get the game there.
strange concept, that you're owed something. people should only be buying consoles if they're comfortable with the libraries and whats immediately available. you don't preemptively buy something with the hope that years from now you'll find a reason to be happy with the purchase