When does a generation end?

[greenmedic88]

I'll say the current generation ends when all players enter the next generation with their next gen consoles.

It doesn't end when one company preemptively quits on their current generation hardware because sales and support tapped out before the competition.

Sega didn't end the 5th generation by introducing the Dreamcast. The Dreamcast was introduced early because there was no point in backing a losing horse in the Sega Saturn.

Microsoft didn't end the 6th generation by canceling production of the original X-box shortly after introducing the X-box 360.

The "Victory Lap" after the current gen ends doesn't begin until all console manufacturers have their new generation hardware available and all remaining sales of their previous generation hardware eventually determine the final tallies.

But I stress this is not to say that these remnant sales mean much of anything other than profits to the manufacturer. They don't determine support for the next generation of consoles as these sales represent residual sales and front line developer support for the next generation is determined well before this stage.