This is a question has been bothering me as someone who’s country was colonized by the British Empire. We were taught about it in schools and how it lost power over time but never how the USA came to take its place especially over such a short compared to the British Empire.
because the UK gave up most of that power in the second half of the 20th century, now the UK is a relatively small country (by area and population) that is increasingly isolating itself from the world (Brexit) rather than attempting to influence global politics a lot more than other countries of comparable size, population, and wealth
But the US is slowly losing influence too. In 1990 its side had won the Cold War, but since then other things have happened: 9/11, Iraq War, George W. Bush, the war on terror, Donald Trump; many geopolitical events of the present can be explained (in part) by the fact that the US is losing influence over the world.