This is a very common belief amongst successful people. In fact, you might recall a few years ago in US politics there was this big "I Did It" thing where successful business owners defiantly claimed they earned their successes without the help of anyone (or any publicly funded infrastructure).

I'm sure sociologists have a name for this, but to me it represents people who have a big hole to fill regarding self-worth. By believing they accomplished something because they are extra-uniquely special is a way to try to fill that hole.

If you take a formerly successful person and have them start over, their stature (titles, money, contacts) can often give them starting benefits that can indeed make their following ventures successful - or at least more likely successful than if they had started with little more than their skills.

There are old, wealthy people who have made a life out of repeating "successes". Some find their way into positions of great global power, and they unfortunately believe they know more than anyone else (and will state such without any shyness).