There was a recent study done by the University of Cambridge which analyzed the black market for fake accounts across various platforms in multiple countries. They found there was a correlation with the price of these accounts and ease/difficulty in setting up a SIM farm for that country.

Snippets from https://www.cam.ac.uk/stories/price-bot-army-global-index

“One SIM card can be used for hundreds of different platforms,” said Dek. “Vendors recoup SIM costs by selling high-demand verifications for apps like Facebook and Telegram, then profit from the long tail of other platforms.”

....

A new analysis using twelve months of COTSI data, published in the journal Science, shows that verifying fake accounts for use in the US and UK is almost as cheap as in Russia, while Japan and Australia have high prices due to SIM costs and photo ID rules.

So the likely outcome of this Korean effort will be to increase the costs for fake accounts but not to entirely eliminate them. With the extra risk of another place for sensitive data to be leaked.