Because he is the coolest dude on the planet. To have him alter his voice would be a horrible affront and would have doomed that film.
-Jason "frankly, Sean Connery could play the love interest of a 30 year old woman right now and it would not seem too outrageous*" Evans
*- Entrapment anyone? 70 year old Sean Connery and 29 year old Catherine Zeta-Jones
Why are you wasting time here when you could be wasting it by listening to the latest episode of the DBR Podcast?