[Nextrush]

The United States would have done fine without World War I as for the British Empire World War I was a fatal mistake a financial disaster the beginning of the end for it.

Beyond that WW I set the stage for among other things the end of firearms rights in the UK the change to the restrictive British gun laws that were celebrated in more modern times.

[BroJoeK]

Nextrush: "The United States would have done fine without World War I as for the British Empire World War I was a fatal mistake a financial disaster the beginning of the end for it."

What's certainly true is that the world would be very different today had the US remained officially and de facto neutral.
So I could make a long list of differences we'd see today, but the most immediate one was victory for the German Empire, which would then stretch from Belgium and Northern France to the Baltics and Black Sea.
France and Britain would have defaulted on their war debts to the US, around $6 trillion in today's values and that would have brought on the Great Depression in 1919, ten years before the actual 1929 US stock market crash.

Sure, people claim, there would never be a Second World War if Germany won the First, but that's pure nonsense.
The fact is that young Franklin Roosevelt learned firsthand from living in Germany (briefly) how arrogant and dominating German elites had become.
Just like Vlad the Invader today, they would constantly push against their weaker neighbors until they found enough resistance to declare war, and so the German Empire would grow until it felt strong enough to take on France & Britain again, this time existentially for them.

Key point to remember: nothing Hitler said or did during the Second World War was new to him, all of it had roots in the German Empire of the First World War.

So we would not like the world that resulted, had the US stayed out of the First World War.