You need to read the famous study by professor Odean of Berkeley: "Trading More Frequently Leads to Worse Returns." Investors buy the wrong stocks and they sell the wrong stocks by a margin of about 3%. They'd benefit by flipping their trading 180 degrees, or not trading at all. There is another study from outside the US and a different time period that concluded about the same thing.
I post these gems often. Experienced investors on SA are often familiar with these university studies. No one on IHUB reads them.