Why do streetsmart people always have the upper hand?

My sister is kind of naive while her now ex boyfriend has always been streetsmart. He broke up after 3 years and already has a new girlfriend so fast. They already slept 2 days after the break-up.

Meanwhile my sister has been talking to a guy online and hasn't even gone out on a date yet. When they were together, from the beginning it always seen like he had the upperhand in practically everything; managing money, workplace experience, moving on from break-ups, finding dates so fast, making friends, providing, etc.

I'll be honest; when they were in a relationship... I always thought that if a break-up happens... my sister has a lot more to lose than him. Why do they always have the upper hand?
Why do streetsmart people always have the upper hand?
Post Opinion