Say's "Law" says that there cannot be a "General Glut", unless Production of another Good (or Performance of another Service, it would Stand to Reason would also Apply) is Insufficient; if it Exists, it will be Bought; if it is Undersold, something else must be Created; for Money is Momentary; it will be Exchanged as Immediately as Possible.
Of course, there are two Problems with that: Gluts do Exist, Especially in Recessions or - Worse - Depressions, and Wealth is often Reserved; even when something could be Sold for Profit, many Wait for a Greater Profit. Also, there are other Considerations than just these Products and Services; even if Ego were Removed, one may Abstain from Short-Term Profits - as would otherwise Inflate one's Ego to Pursue - for the Objective Considerations of Racial Welfare (Literally: Well-Being).
There are three Means of Increasing the Appeal of Existing Supply; either to Create something Better and to Reduce the Cost of the Existing Item or Service, so those not Able to Afford the new one will Settle for Purchasing the old, to Popularize its Conversion to another Function, or to Create something Inferior - Especially if Overpriced - so as to Convince Consumers to Settle for it as is. The latter seems to be Increasingly Common, Despite the Fact that it Bears the Risk that someone will Create something of Higher Quality and/or Lower Price in Spite of it.