in my opinion ,some time you need to deal with high voltage signal connected to input or output ports and have the core implant low power design for low power consuming.
DZC is right, power IC need high voltage power, and driver IC need high voltage too, eg: LCD driver ICs, the LCD often is large 10v, some case need 30v transistor, high voltage is not conflict with low power design, just because the driver need less transistors, and the current is can be retain small,
only the analog need high voltage power, but the logic is low power.
High volt CMOS is more and more applied in various power supply system.
process with high volt option provide the mothed integrated power deive
in single chip .for example, 7-12v for lithium charger application, up to 40v for LCD. 18-40 DC/AC ...
HV CMOS in power supply design, LED driver, laser diode driver... and many applications in automotive industry.
There is some tricks to use standard CMOS circuits above the breakdown voltage (tricky cascode structures).
Springer pressed a book in this topic, but now I don't have enough money to buy it:-(, and I can't find in electronic format.