What means something is that Mao kicked out the European free-ports, those colonialist enterprises run by colonialist countries.
It had to be done.
The Brits still had their Island colony.
The ruling class on that Island colony hadn't done a very good job for China, when they were in power - and now they ruled their Island at Her Majesty the Queen of England's sufferance.
In the thousands of years of China's history, their governance was the nadir.
China now had to fend for itself outside of and ostracised from the American/European economy, in a condition that was totally undeveloped and totally the product of neglect.
For all its faults, China is now/soon the #1 economy in the world.
That happened quickly, considering the size of the engine.
The Chinese invented the concept of "state capitalism" decades ago, whereas most Americans still associate China with a nebulous hate-word 'communism', think its economy has something to with "Marx", and beyond those insights don't have a clue.