There is such a thing as dilution and more so, with day trading because day traders are fighting over shares of very thinly, traded penny stock companies. Now, this affords huge opportunities for those so called day trading gurus. They get to front run those penny stocks then, tell their legions of students, this stock is going to the moon. Once, they pile in, the stock rockets, the guru sells his shares at the top. Shorts it on the way down and makes a bundle yet, again. Now, the extra benefit for the gurus? Now, their students are salivating at the next penny stock because some of them actually, got lucky and made monies. Majority lost their shirts. Guru tells them to practice and get more of his training. Ha ha ha! Sorry, this is too funny.
Actually, you are mistaken, PPS developed by Curtis Arnold and I won a U.S. Trading Championship in 1992 using it for 5 months made 214% return, Arnold then sold it in book form and stopped working for over a decade, Gary Smith sold his system for under $100 and by 2nd day everyone in pit had a copy by 2nd day and it stopped working, Oddball made by Mark Brown used to work well years ago then it stopped, 1990's Saddleberg S&P 500 Break through did well for hand full of years then broke down, Nofri Congestive Phase System worked well till someone posted it on bulletin board. There are dozen others, but all had same end results. It is just too easy now to just take other side of retail trades, if you know what to spot. Most of my signals during day session, automation set up to look for retail failures.
Sure, if these systems have no real trading edge to begin with. The famous Turtles made 100 millions with a simple Donchian system. Then they noticed that the results were rapidly deteriorating (due to increased competition from other copy cat traders) so they changed the 20 day look-back period to 40 days and BINGO, they started earning money like bandits again.
Did you buy each of them or gotten them from the author, if not you have zero knowledge. And yet you speak of changing look back and "earning"? money, so this is first hand knowledge or is this hearsay. I made 4 changes to PPS in later half of 1993, no one has my changes and does far better as far as reward to risk, but will never make 214% again. Trading on each signal of any method has some luck, more experience one has gets more luck, no experience has bad luck. Long term you can make a little or huge or lose, just never know, have to keep feeding in orders and just "TAKE IT" !!!
True to a degree about my mechanical system. But I was always a discretionary trader using filters such as the Transports, Utilities, Tick, Trin, divergences between indexes, and more. I was never able to systemize those discretionary aspects into anything mechanical. Never believed there was any mechanical system that would work because trading isn't that easy. Noticed there is some mega vendor out there who uses a lot of my old methodology. Of course, like 99.99% of vendors out there, he couldn't produce a profitable real money trading record if his life depended on it. Why people buy expensive stuff from the Dream Merchants who are unable and unwilling to validate their ridiculous claims via real money statements is beyond me. I guess PT Barnum was right about........