Why don't they give parachutes? Because by the time the plane was travelling slow enough to use them, it'd be on the ground already, one way or another.

Seriously. Do y'all not realize how fast a commercial airliner goes in comparison to a C130? You'd be torn apart as soon as you got out of the door. Not to mention, you'd probably freeze to death or suffocate before you got a chance to open your chute.

Plus, as has been mentioned, it takes a little training to use a parachute -- especially mass-produced ones, like they'd have tens of thousands of bought by airline companies. At least 90% of the people using them wouldn't know their ass from a hole in the ground, anyway.