Dont get carried away by pseudo nationalistic jingoism. India can never be THE World Leader, THE Super Power. Dont be mistaken, India will be a power to be reckoned with, a powerful player in world affairs just like UK, France, Germany or even China. But neither India nor China can ever replace US or usurp the role US plays in present day world. And, ATM, there are very solid reasons why.
You talk about empires. But have you ever noticed that those empires which "rose and fell" were political empires, in the sense that empires expanded by acquiring/annexing foreign lands and spent huge resources in exercising control over those foreign lands. Any weak policies at the center of those empires ultimately led to loss of control over the acquired/annexed lands.
Contrast that scenario with what US does today. US does NOT spend any money on annexing or acquiring foreign lands to expand its "empire", nor does it spend huge amounts to maintain those lands. Whatever US spends is recouped by making other countries to share the burden or make them pay in kind - and actually allowing those countries to share the rewards as well. Actually a 'win-win' situation for both, adding the spark in the economies. US dominates by controlling the world economy. Who in India has the political guts (one has to consider the local electoral repercussions of initiating such politico-economic reforms) to actually turn the economic growth into a vision for dominating world's economy? Local politics is still stuck in 'roti, kapada and maakan' whirlpool.