I meant quite a few political families. BTW if you include the Roosevelts (grandson), that's three. But there have been many other families with multiple governors, senators and other important posts. A president in the USA is directly elected, and so the chances for a son to succeed the father shouldn't be as big as in a system where a political party nominates the PM, and political parties can be controlled by families. But many families have been very powerful and influential in US politics at all levels. The mayors of Chicago, the Daleys for example.
The next part of your statement is rather weird. True, India is not a superpower and the US is. But that is not because of political dynasties, there are a million reasons for that. This is like some Pakistanis who enter any Indian military related thread and say "oh but there is poverty in India". Well, duh.
In that case there are many countries where children have not succeeded their parents as rulers, and yet the country is not a superpower. I will make a wild guess and say that such countries outneumber the number of superpowers.

See how that's a non sequiter?