Do people leave companies after a few short years because they're job hoppers? Or do companies drive them away with constant focus on profits, redundancies, cut

Do people leave companies after a few short years because they're job hoppers? Or do companies drive them away with constant focus on profits, redundancies, cutbacks, and all these wonders of modern management? I'm more of the opinion that people 'jump ship' because they're worried that the rug is about to be pulled from under them at any moment by management.