Just because a computer game keeps you up all night doesn't mean you're really learning anything. Not all flow is good. Wartime in general is a demanding, challenging, flow-prone experience, which explains much of the appeal of gangs in inner cities. Likewise, being a corporate raider can be flowful, even if you are doing major damage in the process. Bureaucracies are not flowful.
Startups are flowful.
Kids raised in a home where they are challenged yet secure will be more able to achieve flow. Parents who push their kids, while setting firm boundaries and giving lots of support, will find their kids eager to flow. But a free society enables more different kinds of flow experiences, and more outlets for flow, than an unfree society. Religion can be a powerful aid to flow. If you believe you know why the universe ticks, and if you believe that your actions somehow affect the balance or at least your own fate, then almost everything can become flow.