Dropping the C2D?

Howdy all. I know it's pure speculation, but, looking beyond Lion, when do ya reckon Apple will stop supporting the core 2 duo, as they appear to be binning the old core processors with Lion?
I reckon there'll be at least one more OS update after Lion before they're unsupported, although considering the shear volume of Macs based around them (and hence pissed off customers when it eventually happens), there could be more.
I'm not entirely sure what the point of this was, really..............