Success in life is more correlated with ambition than with knowledge: an average educated but very ambitious person have more probabilities of being successful than a super smart individual that is ambitious but about knowledge and ideals, not money.

If you link this lack of focus in taking profit from your actions in life with a master in a struggling field, you are on your way to an underachiever life. That's me.

That probably depends if your definition of "success" is centred around "money" or around "happiness". (Or some other factor that I haven't considered).

Not so. Renaissance people (there are a few, even today) tend to end up underemployed. If you want to be a "business multimillionaire", you go the opposite way. You focus, you narrow yourself, but you have to focus on something that can actually make you money (i.e. not medieval history).

Why are most of the true Renaissance people underemployed, obscure, and financially mediocre? It's because the only thing that can tell a polymath from a dabbler is time.