While you properly note that no one can resist the effects of environment, one can, however, be aware of them and can choose to modify a limited number of specific effects. Otherwise, we would always buy the store out as it were (store being designed
to mightily encourage the browser to spend). Voila! A function of the conscious mind! Suppression of subconscious drives, and, if necessary, retraining to modify behavior into the future.

Our best guess ala Libet is that consciousness is a President ruling over a vast machinery of government. By far the greater part of what (s)he “rules” over is beyond his ken. Most of his/her orders are deeply conditioned by that government itself each part of which is far more capable in its purview than (s)he should ever be. (Just as trying to micro-manage all of our subconscious functions would leave us unable to walk or drive a car, Presidential micro-management is hugely counterproductive.) It’s a strong system which is why our brains and our governments use it. One simply has to realize that one of the effects is that, no matter how impressive and necessary the President, (s)he only makes a small part of his/her own decisions.