If Xb one truly fails, i.e. gets taken off the market, then yes, some people will go to Wii U. But PS4 would benefit more. And lots of people just won't bother with consoles.
But yes, if 3rd parties can't make enough money from a dominant PS4 and a failed, but still on the market, Xb one, then they will release games on Wii U to try to get every last possible sale. The cost of making a decent Wii U port should be cheap enough that just a few hundred K sales on Wii U will be profitable. And more 3rd party multiplatform games on Wii U, with Xb one being a bit of a turn off should help Wii U to sell somewhat better.
But "flourish" might be a bit strong of a word.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix
