I guess he said that BEFORE they released their new 5V devices then ;)

Freescale have wide voltage parts, (RS0 core) with even lower prices than NXP, so it seem the claims of 3v3 ceiling based on area (aka cost), are a (large) red herring.

[Freescale use a buried regulator, and have no problems combining 5V io and lower core, in a sub 50c device ]

Those 5V Nuvoton parts say "starting at US$0.55 in volume"

Area claims relate to the lithography, NOT the Chip Voltage.
The voltage is a function of the oxide thickness, and many FAB processes can use more than one thickness.

Easy enough to go fine in the core, and thicker/larger in the IO and regulator. {Probably also helps the ESD ratings too...}