Wii u had 60 exclusives in 2015 while the PC had 19, PS4 and 12, and the Xbox One had 3.

[Never]

I remember when stealth inc 2 (probably my fav wii u indie game) came out as exclusive to wii u (At least temperately) the devs said they did it for exposure. That seems plausible with the current saturated indie market.