"You might not have found any games that suit your skill set, but that doesn't mean those of us who have are just making up stories about making money"

Sorry, somewhat trite and unfair, but, if there is a gambling-like dopamine reward cycle occurring, then the users would have a hard time being truly objective about any productivity boost in total. They may instead focus on the 'wins', without taking into account any overheads or 'losses', much as a gambler would do.