And how did the UK acquire the strength needed to take those colonies? Would-be conquerors are a dime a dozen, empires as successful as the British not so much
I mean, I don't think "well, they used to have a big empire" says that much about the current state of the country. Shift the dial around a century or so, and you hit at least three other Best Empire countries (Spain, Portugal, Netherlands). I think the British empire is particularly memorable because it was basically the _last_ one (pedantically, shreds of the Portuguese one held on for a bizarrely long time, but the British one was certainly the last one to peak).
it's also probably memorable because it was the largest empire in human history with like almost a third of the world in its possession? It's arguably one of the most influential
What you refer to as strength is not potent anymore: you can surprise uncontacted peoples only once, and nowadays there's UN, the Geneva Convention etc. to stop such dehumanization that enabled the colonizations.
Most colonies back then had no big picture view of the world. They had no idea what tactics were being used against them and were hyper focused on their local situation. Internecine warfare within Europe and trading across the world gave the merchant companies training and advantages that no one else in the world had. Things are quite different now.
Good topic for a book me thinks.
There is a book on precisely this. Uncommon wealth: Britain and the aftermath of empire.