Your logic's a bit... erm, fuzzy, to say the least.
Handheld gaming took off in such force largely due to market stagnation for consoles during the 2004-2006 period, combined with the Blue Ocean Strategy effect of the DS. Your numbers don't really take into account that most of those handheld sales were DS units, and most of them sold to non-traditional audiences.
Actually, what we're witnessing from 2006 onwards is the same thing we witnessed happening with handhelds from 2004 onwards: a small bubble rising and growing massive, with an inevitable "pop" in the future. The handheld "bubble" appears to be "popping" (or at least hitting its apogee) this year, meaning we can expect the console "bubble" to keep growing until about 2010 before it hits a similar apogee.
Sky Render - Sanity is for the weak.
