This could be a naive question, but everything I've heard is that coronaviruses don't disappear, they just sorta integrate and mutate into our normal "known set

This could be a naive question, but everything I've heard is that coronaviruses don't disappear, they just sorta integrate and mutate into our normal "known set" that we deal with year-to-year. If that is true, doesn't the strategy taken by SK and NZ put them at continued risk for a another outbreak if the virus sneaks back in? Without a vaccine, and then significant uptake by the population yearly, doesn't the risk of covid-19, and its mutations, come back every year?