Its because people intuitively understand that extraordinary claims require extraordinary evidence. And we also understand that people selling systems are almost always frauds, in part because if you had a great system you wouldn't flood the market with competitors reducing your returns.
None of this is saying that Sykes didn't turn a tiny sum into $2M or whatever. Someone wins a lottery every day. Every year someone wins the WSOP main event for millions of dollars, but almost never the best player and sometimes the winner is a terrible player. I used to play in a high stakes game built around a huge fish that had won 4 WSOP bracelets, won WSOP Player of the year once and would have won it twice if they hadn't changed the rules. And these famous "winners" get to become poker coaches because clients don't know how to play poker well so how would they know how good their coach is?
Too my shame I've spent enough time around the casino to know a few gambling "experts" that were so good at it that they made a living selling their sports betting picks. Then I found out that the key to the business isn't handicapping, it's deluding lots of wealthy clients with your reputation and lifestyle. Even though your picks are pure guesswork, half your clients will still win, and they'll stick with you even through long losing streaks because you are a "proven winner".
I've often wanted to perform the following experiment, not for my personal financial benefit, but for science;) I'd start sixteen anonymous internet accounts that give out free stock picks. Each pick would be selected for high volatility and momentum to maximize the potential upside, esp. if they have an impending catalyst. After a few picks roughly half my accounts would be losers and the other half would be winners. I'd shutter the losers and start charging for the winners. Again after a while I'd probably only have four accounts that were winners and one or two that have outstanding returns. Again I'd shutter the losers and unveil myself as the master trader behind my highest return account, and market the hell out of my service, start selling books, training videos, more personalized stock picking services, etc. Over time I'm going to trail the market, but many clients will stick with me because I'm a "proven winner" much like Cathie Woods.
Again, I am not saying that Sykes is a fraud, I'm saying I don't know and haven't seen any evidence to convince me. I think it's healthy to always be skeptical of huge claims without corresponding strength in the evidence. Sykes may have parleyed a great run as a trader into a coaching business, but that doesn't tell us whether his run was luck or skill, or that he is able to coach clients into achieving similar levels of success. After all if you have thousands of clients statistically at least a few dozen would end up with amazing results just due to pure luck.