Joseph,
I didn't take the time to research the chart you posted but it appears as though they stop the one model when the next one comes out. I'm not sure if that is accurate or if as watt100 mentioned, they have a lot of inventory. I would guess they have some sort of production overlap.... not sure how much, generally.
Allow me to clarify: right now, you can still buy a 60D from Canon. Are they still in production, or are they left over inventory? 70Ds were available last summer. The Canon Museum site says August, but I think pre-orders were fulfilled in July. Did Canon have a full year of inventory on their shelves when they brought out the 70D?
I tried to find when a now discontinued model went out of production but no luck, so far.
Kim (the male variety) Canon 1DX2 | 1D IV | 16-35 f/4 IS | 24-105 f/4 IS | 100L IS macro | 70-200mm f/2.8L IS II | 100-400Lii | 50 f/1.8 STM | Canon 1.4X III
RRS tripod and monopod | 580EXII | Cinch 1 & Loop 3 Special Edition | Editing Encouraged