I would say England is just as guilty as the Duch for hiding behind the USA and giving up two possible futures

They are the 13 colonies and the conquest of France without which England would be limited by its geopolitics

The Dutch Republic were interested in defense not expansion and in turn lost more and more power in the 18th century

Also they spent over 100 years in a state of constant War with Spain than France

And where exhausted from these conflicts may be even psychologically not just politically

You could say England went through the same thing after the 100 years war with France 1337 to 1453

Then the end of world War 1 in 1919 and the failures of the post war Lloyd George government

When Churchill was writing that biography he was still in the mindset of England having vitality

He was delusional in that respect due to being a patriot but he has blind spots

The USA is not declining military or economically it's declined began psychologically

Empires don't just loose power straight away it happens over time the Rome Empire is a classic example with the fall starting

With the murder of Tiberius Gragus in second century BC

For the British it's weaknesses and strengths were forged in the late 17th early 18th centuries

For the kingdom of France it was Louis XIV that killed his own Dynasty

Some times it's due to institutions, political culture, individuals or others that lead to the end of Empires or Kingdoms

You could say the end of a united great Britain start with the Labour government of Tony Blair

And that we are still falling