Then there is something wrong with the implementation used by your phone.
When traveling internationally, I generally turn the cellular radio off on cellphone. In that case, the battery lasts almost a week, even if I occasionally use WiFi to surf the web or (primarily) update emails.
A good implementation of ARM (remember ARM doesn't make processors, they just make IP to go into a processor) can be a very low-power device. Yours doesn't sound like it is a good implementation.