To me the decades old question should be 'if a player can pick winners, why isn't he picking winner and betting instead of marketing his picks or service'?
And this applies to other forms of gambling. Those that can win at blackjack do it. We don't make a living writing books about it. Those that can win at machines, do it.
Anyone writing books or selling information (picks) rather than betting and winning themselves, 1) probably isn't a winning player and 2) is no longer operating in the arena of gambling. They are marketing.