remarkable s&p

Came up somehow in 1999 Chuck LeBeau is a profitable system for trading futures on the SP500. Test it on historical data with 10/17/1988 to 12/31/1998 looked promising:

There was a total 114 deals both long and short with a profit factor already in 4,69. And the percentage of profitable trades 84%.
What is there to think — you have to buy and trade. Let's admit, bought and started trading. This is what would have happened in the following 11 years, beginning with 1999 till today:

AND, for better clarity, overall result for 23 of the year:

Out of luck someone, who are looking for a highly profitable system in 1999-2000 years.
Why did this happen? The fact that the system was invented and began to be sold in 1999 year and exactly from that time it stopped working, is it a coincidence or not? Maybe not only Lebeau revealed this pattern., allowing you to earn a stable income, and many others, and therefore the market as a self-regulating organism has changed, fixing inefficiencies identified by many observant traders?