Perhaps, perhaps not, this is an explicit limit of Femi estimates.

But you do also have to include the power cost of displays when the game machine doesn’t have one built in, adding 10-120W.

And the older consoles didn’t all vanish into the ether when new models arrived; my brother still has an original Xbox 360, and not for lack of money to upgrade. So I expect many of its contemporaries to also contribute to the total number of gaming units, not just total sales of most recent Xbox + most recent PlayStation + most recent Nintendo console.