This kind of rhetoric is really only applicable for countering the most hyperbolic of critique. Further, I don't understand why the 360 and PS3 launches are held up as the barometer of successful launches. If the argument is "no console can launch as poorly as the Wii U and go on to success," then that's clearly absurd. I agree. But if the argument is "everything's fine, it's beating those platforms at similar points in their lifetime," then I would argue that this is equally absurd.
I don't know if cries to sack Iwata are appropriate or not. That may be a rash decision, particularly depending on who they might have in the wings to replace. However, if it's too early for that, it's not too early to call a spade a spade and conclude that the launch is disappointing thus far. They have historic sales data. They have market researchers. They know what games are coming. If 5.5 million was an absurd longshot that was never going to be hit, and the real target should have been PS3/360 levels, they would have projected 4 million or lower from the start.
As is, it's a 27% decrease in their official projections. All the handwaving and spin in the world doesn't change that reality. There's plenty of time to get things on track, I agree. But right now, thing's aren't looking hot. And the competition is gearing up their new toys for the end of this year/early next. The road to recovery isn't insurmountable, but the current trajectory certainly doesn't paint a picture of inevitable success either.