Does Say’s Law Really Work?

Say’s Law: a principle stating that supply [or production] creates it’s own demand. Question is: does it really work? To say that supply creates it’s own demand is saying that if you produced 45 million 1970s style typewriters, then people are going to want it. In order to increase demand, one must create a product that will appeal to the public, then sell it at a reasonable price. Also, entrepreneurs create jobs when there’s a demand a product they’re willing to sell.

So ask your self, can this really be applied to modern economics?