If we stop wanting altogether, we would never achieve anything.
 
True. But what the Buddha says is that when our desires, our craving, our constant discontent with what we have and our continual longing for more and more does cause us suffering,then we should stop doing it. He asks us to make a difference between what we need and what we want and to strive for our needs and modify our wants. He tells us that our needs can be fulfilled but that our wants are endless - a bottomless pit. There are needs that are essential, fundamental and can be obtained and this we should work towards. Desires beyond this should be gradually lessened. After all, what is the purpose of life? To get or be content and happy.