Considering that at the similar point in it's lifespan, the XBox had only 1 holiday season under its belt (having launched in February), it doesn't sound too impressive.
The graph, however, is far more impressive, as it shows the 360 now exploding in comparison to XBox. As much as 1.5 million consoles this generation is possible, which would be huge growth.
But then things are put back in perspective by adding a couple other lines for other consoles. I don't mean PS2 and DS. I mean, say, WonderSwan and WonderSwan Color.
http://www.vgchartz.com/hwcomps.php?cons1=X360®1=Japan&cons2=WS®2=Japan&cons3=WSC®3=Japan&align=1
Selling 1.5 million consoles instead of .5 million may technically result in a "growth in marketshare," but it is still a very, very poor performance. Saying this growth bodes well for future generations is like saying SEGA's growth from Master System to Mega Drive would help Saturn. Too much can happen in the meantime (though MS are unlikely to have 8 consoles on the market at once) to negate it all.
"[Our former customers] are unable to find software which they WANT to play."
"The way to solve this problem lies in how to communicate what kind of games [they CAN play]."
Satoru Iwata, Nintendo President. Only slightly paraphrased.
