From what I understand, the medical community is treating this outbreak with such extreme measures because this virus is a perfect storm of factors that could lead to a new annual disease emerging, just like the flu and cold. It's deadly enough to become a major global concern and transmissible enough that it can continue spreading via asymptomatic hosts and other viral reservoirs between outbreaks. The jury is still out on the virus's rate of mutation but other coronaviruses, like the ones that cause a tenth of common colds, are known to mutate rapidly.

If we fail to stop the spread of the virus now, it may become a fact of life with an even higher annual death rate than the flu. We've already got plenty of infectious diseases and based on the data so far, it's worth extreme measures trying to stop it.