Generally you only see players all-in before the flop with A-K in tournament play. It's just too risky and marginal a play to be even remotely justified in a cash game where players aren't forced into desperation by continually increasing blinds. If you are calling all-in after heavy action, you're probably dominated, and at best your opponent is a slight favorite against your draw, and if you're moving all-in, why risk getting called by some pair (which may dominate your hand) and gambling for all your money in a situation where you have at best a minor disadvantage?