The Economist blog content tends to be pretty lightweight and casual, a little daily snack in between the weekly full-course meal of the print edition (whether or not you read it on paper).
I'm a bit torn. On the one hand, the fact that China was the world's biggest economy until 1890 wasn't very significant in terms of its influence on world history. I don't mean this in a Eurocentric way, but in terms of the fact that China stayed largely within its own borders and wasn't in intense technological competition with the West; the size of the economy was largely a function of its huge population, which remains somewhat true today.
On the other hand* population can't be the whole story, or India would have a similarly-sized economy. Chinese GDP per capita may lag behind the west, but there is no question that the country has profited hugely from becoming the modern 'workshop of the world.' These profits must be set against the negative externalities of chronic pollution and a increased internal political pressures, but it's impossible to ignore China's enormous strategic advantage in this area.
How they will leverage this is another question, as the country is facing an intense demographic squeeze that will leave it with a disproportionate number of elderly people within the next couple of decades, but without a strong social safety net or high levels of education. Obviously China's leaders have no intention of allowing the country to enter a Japanese-style economic stagnation, but how they will address that challenge is anyone's guess.
* Harry Truman once demanded that he be sent a one-armed economist who would supply him with one opinion instead of two.