That argument doesn't hold weight when half of the launch lineup was mainstream or M-rated games.

The impact of which was blunted by the fact they were almost all late/inferior ports of games people could get on their PS3 or 360. Nintendo's focus this gen has still clearly been on E-rated cartoon games, and their lineup is severely lacking in M-rated exclusives.

Which has nothing to do with ur original statement. Lack of M-rated titles has little reason to do with Wii U poor sales.

Yeah, the Wii U doesn't have much in its offerings in terms of total amount of software available, nor in diversity in genres or target audiences.  If you love platformers, E-Rated games and party games, the Wii U is heaven but if you don't, there isn't really much else the Wii U has to convince you to buy one. 

Yes, it does. Nintendo's software output does not align with what mainstream gamers these days want.

A few late/gimped M-rated multiplats early in its life don't change that.

So Nintendo should completely change who they are as a company to copy the exact same thing that others are doing? That sounds like an absolutely awful idea.

They don't need to become exactly like Microsoft/Sony, but they cannot keep running their business like it's 1995. It's not working. They must adapt to survive.

If anybody is running their business like its 1995 it would be Sony, PS4 follows the exact same formula and strategy as PS1.

Sony caters primarily to what today's mainstream gamer wants, hence PS4's stellar sales.

By contrast, Nintendo does not meet the needs of your average gamer in this day and age, hence Wii U's sales.

Ur contradicting yourself, u said Nintendo is failing because they act like it's 1995 yet Sony acts like it's 1995 and has seen a lot of success.