Why is it difficult, if not impossible, for us as individual investors to use our ability to analyze publicly available financial data and economic trends to identify individual winning and losing stock investments?

Trading costs are just too high, making it unprofitable to buy different shares of stock.

In the United States, share prices are set daily by officials of the Securities and Exchange Commission $($SEC$).$

Stock market prices react to new information too quickly.

Legal restrictions prohibit sophisticated individuals from using their financial analysis of publicly available data to pick winning and losing stocks.