In the 18th and 19th century, Britain as in the forefront of the industrial revolution with the invention of the steam engine. She was able to build battle weapons, warships and in the early 20th century.
With newly acquired weapons and ocean going warships, she ruled the "7 Seas" and managed to conquered the 3rd world i.e. Africa, Middle east and Asia.
True. The technologies were naturally transferred to friendly allies like the US, Canada, Australia etc. with traditional British links. Then Germany, Japan, Russia etc. tried to catch up which ended up in 2 world wars. However, the balance of power is still very much with the English speaking countries, just a change of leadership from UK to USA, all still family.
When the colonies and other 3rd world nation began to industrialised and caught up with Britain, she had lost her advantaged in weaponry. The sun finally set on "Great Britain" and the same shall apply with "USA".
That's why they're very concerned about other countries having nuclear missiles. At the moment, only Russia can hit them with nuclear missiles. Otherwise, only them, i.e. US, UK and France, can hit any country in the world with nuclear missiles. That's the nuclear deterrent, standoff and status quo. China, India, Pakistan all have demonstrated and declared nuclear bombs, but lack the range of delivery, they can threaten neighboring countries only.
Then, there's conventional war capability. From the Qing Dynasty days till today, UK and US warships and troops could land on and attack China (or anywhere in the world) at will, whereas China still don't have that capability to project power over distance. In the 2nd WW, Germany and Japan proved to be developing such powers, but were defeated and went on their side. Once again, only Russia is the counterbalance.
So as I see it, a global powershift from the Anglo-American axis is highly unlikely in the foreseeable future.