Low sales of the Wii U weren’t the only reason Nintendo decided to not offer dual GamePad support on its somewhat underwhelming console.
As such, “the development just never proceeded” and, with the Wii U becoming a rather short-lived console in the grand scheme of things, dual GamePad support just “never came to pass”.
The decision was also due to a general lack of suitable games to actually make its implementation worthwhile, former Nintendo of America boss Reggie Fils-Aimé has said.
Answer was ‘yes’, but the install base never got large enough that that type of implementation made sense.”