If DS was a fluke where's the "inevitable" handheld decline?

[zorg1000]

LuckyTrouble said:

But the 3DS userbase is not 60 million. It has sold 60 million, but mid-gen updates make it a whole lot harder to estimate the actual userbase.

The same can be said for any device that recieves revisions.

GB/PS1/GBA/PS2/DS/PSP/360/PS3/3DS and soon to be XBO/PS4 numbers are all inflated from having successful revisions.