The fraction of people needed to create herd immunity in a population is 1 - 1 / R0. With R0 at 4-7, that means about 75-86% of people within the population need to have COVID-19 antibodies before transmission naturally dies out through herd immunity. With current case numbers, China doesn't have anywhere close to this many cases - it would imply ~1B infections within the country rather than the ~80K that have been found so far, off by a factor of 10,000.
I think a likely outcome is that the current outbreak dies down, then it either flares up again from some undetected cases or is reintroduced from another country. But then, with the initial media attention elsewhere and COVID-19 symptoms basically looking like the flu, they'll just let the sick die rather than re-introduce draconian quarantine measures.
I think a likely outcome is that the current outbreak dies down, then it either flares up again from some undetected cases or is reintroduced from another country. But then, with the initial media attention elsewhere and COVID-19 symptoms basically looking like the flu, they'll just let the sick die rather than re-introduce draconian quarantine measures.