Perhaps it is incorrect to say that you cannot do it, but there will be times during a tour when you will want lower gears than a 50-34 compact can provide.

Imagine you've been in the saddle for the past eight hours, fighting a headwind while hauling your gear over rolling hills. You're exhausted, it's starting to get dark, and your destination for the night is at the top of a what looks like the steepest hill you've ever seen. This is when you want really low gears.