I don't think it proves it, since Sony has showed with the PS2 that the razorblade tactic can work out nicely.
What it proves, and it is quite obvious, is that a profit-from-the-beginning model is very healthy for the company, specially if the console takes flight, like the Wii. However, Nintendo also had profits with the Gamecube, a console that I owned and really liked, but was never much of a seller.