Because of the level of development at the time.
While all the continental European powers had to maintain large land armies for protection against each other and land invasions, England is an island who built the worlds greatest navy which is used to project its force with no risk of France or Germany really crossing the Channel with troops. No worries of Napoleon or anything of the sort, for the most part. When air warfare became a reality, power was ceded to the US.
This can also be applied to the US currently, since it has a two ocean buffer and there is no risk of land invasion from Mexico or Canada, meaning rather than maintaining an expensive land army, they are able to use those funds in other more constructive forms, hence their status as a hyper power.
There are multiple other factors, but this one is particularly important. Discount everything else in this thread, it's nonsensical. How can colonization/"exploitation" explain their power?

Colonization of other nations was a
result of their power.