Cramer did well in the late 80s and 90s with his hedge fund where he traded (self-admittedly) largely on insider information. Once reg FD was filed he quickly wound up his fund in 2000/2001.
He was insider trading how do you think he beat the market. His fund returned something in the range of annualized 19% after 2/20 over 10 years which is impossible for a monkey like him unless he has an unfair advantage. Immediately after insider trading became illegal he wound up the fund. His returns on his charitable portfolio trail the total return of the SP500 in a big way over 10 years, even without 2/20 fees. Insider trading skill yes. Stock picking skill no.
The scam back then was that companies would sandbag their earnings forecasts and then tell the analysts what the earnings would actually be. The analysts would share that with their favored customers who would buy the stocks ahead of the earnings announcements which would always be a beat. Reg fd made it illegal for a company to give info to one investor and not the rest of the investors.