If you've done any sort of optimization / operations research, you know that most things can (sometimes unhelpfully) be rephrased in terms of an optimization problem. If "success" (whatever that means) is to be seen that way, then (some) successful people probably do both: set constraints to reduce the search space, and chase goals within that space (optimization). You can relax some constraints but then you need to be better at optimizing fast, or willing to accept other goals / winning conditions (get rich by being a criminal).