Based on the latest Media Create hardware numbers...
DS vs PSP: Weekly shares of 59.5 / 40.5 bring total shares to 68.9 / 31.1. If DS stopped selling and PSP continued at this week's rate, it would catch up in 88.5 weeks (September 16, 2010).
X360 vs PS3: Weekly shares of 24.5 / 75.5 bring total shares to 24.0 / 76.0. If PS3 stopped selling and X360 continued at this week's rate, it would catch up in 93.1 weeks (October 18, 2010).
PS3 vs Wii: Weekly shares of 33.6 / 66.4 bring total shares to 26.1 / 73.9. If Wii stopped selling and PS3 continued at this week's rate, it would catch up in 81.0 weeks (July 26, 2010).
Week over week Nintendo systems are slightly down, while everything else seems up by a third-ish.
Well damn. I'm starting to think my hypothesizing about PS2's 10K hardware days being over lit a fire under it, since it starts off 2009 at over 12K.
That is down from over 32K the year before, though.