Centralization offers efficiency gains, else it won't happen. Your imaginary company in South Korea likely makes a million horseshoes employing only 1000 people, and the horseshoes are good quality, and the price is like 5% of the price of a handcrafted horseshoe. Many more people can afford horseshoes as a result.
Many fewer people can afford horseshoes as a result because all the money is at the horseshoe company.
But think of the jobs! There used to be a million people involved in horseshoe-making, now there is only a thousand, and the rest of that million now has to do something else! And since there is literally nothing else for them to do, they'll have to die out :(
The most bizarre thing about the economical systems is that there indeed were cases where former workers of the industries that collapsed/disappeared indeed went the way of the dodo.