"Samsung’s Galaxy S10 5G dominated sale in the second quarter, followed by another phone available in 5G, LG V50 ThinQ with a share of 7 per cent, according to the data compiled by industry tracker Counterpoint Research." These latest results confirm South Korea's position as the first leader in 5G and show what's possible.
2 million Koreans have 5G phones. KT and SK are confident 10% of Koreans - about 5 million - will have 5G by the end of 2019. They estimate 30% of Koreans will go 5G in 2020. That would require well over half of the Korean phone sales in 2020 will be 5G.
If China by the end of 2020 matches Korea's 2019 figure of 2019, that would be 140 million. The US would be ~33 million. Almost all estimates except mine are lower than that.