largest economies in history that failed

Qing empire - Largest economy in the 1600s. Collapsed in 1912.

Mughal empire - largest economy in 1642. Ended in 1739.

Ottoman empire - third largest empire through the 17th century. Collapsed in 1922.

British Raj - second largest economy in the 1860's. Collapsed in 1947.

West Germany - Third largest economy in the 1950's. Ended in 1989.

Soviet Union - Second largest economy in the 1940's till 1970's. Collapsed in 1991.

What is common among all these empires that fell?

Outside forces tore them down.

When a great economy becomes too weak to defend itself from outside influences. That is when it fails.

Today China and the US are in direct conflict with one another. Both of them vying for the same parts of the world and their share of the economic pie.

One of these economies is guaranteed to fall lower down the totem pole of world economies by the end of the century.

Whether it be in the form of the US falling to second place, or in the form of China falling to third place and beyond.

Historically, all great empires are replaced by their betters, never by those worse than them.

China cannot truly replace the US until and unless it surpasses the US in the tech field completely.

Size only goes so far in the battle of empires.

China remains consistently 15-20 years behind the US, while its demographics continue to worsen every decade. This guarantees that the Chinese empire is the one that will fall into decline in the future.

Size doesn't matter when one side has a gun and the other a spear.

Conclusion:

Empires rise and fall. This trend will continue well into the future. Some parts of the world are like the Phoenix of myth. The empires fall, and whatever remains rises again even further to replace whatever was broken.

Russia is one of the outliers in this regard in that it never managed to recover to match the economic peak of the Soviet Union.

An empire that cannot out compete its own past can never grow to greatness.

The EU today suffers from a similar fate, as the Roman empire before it was far greater at its peak than the EU of today. Once again the same lesson is repeated. Empires that cannot out compete their past peaks are guaranteed to fall into decline.

The US has out competed the previous greatest empire ( The British Raj ) in all categories except for land area and population.

With the conquest of the moon, the US would unconditionally become larger than the British Raj at its peak.

The last remaining challenge for it to overcome to beat the past would be for its population to cross 531 million humans.

At current rates the US will have surpassed the British Raj in terms of peak population in another 80 years.

In conclusion:

The US empire is 80 years away from becoming the greatest empire ever in the history of mankind by every single metric if current trends hold.