A 50% chance to lose money per year still allows for very long strings of success. Some strategy's trade ~80% chance of a small win for a ~20% chance of a large loss which means lucky streaks could last for decades.
So, basically you are saying that it's all gambling and nobody has a better strategy / better information than everybody else. Some are just lucky and it is all because of the survival bias.
I agree with you in that it is a possible explanation, but I disagree in that it is the only one possible.
I feel that what he's saying is that it's hard to tell if somebody actually has a working strategy or it's just gambling, they can be nearly indistinguishable, and (given the number of people) someone showing a streak of successes is really not much evidence that it's something beyond luck.
They may have something, but since you can't determine if it's so and there is a lot of just gambling, then most likely it's that.
That's part, but the reverse is also true. Someone could lose money and still have better odds than normal. Something like skill adds 5% then luck adds or removes 30%.
I didn’t gather that from what he said at all, personally. I interpreted his comment at face value; it is possible to pull a profit over an arbitrary period of time even with 50/50 odds.
