The measures they are taking is not so much about stopping the spread, that is impossible. It is about slowing it to the point our healthcare system does not get overloaded and people who might have lived die. Even though the death rate is low the hospitalization rate is rather high. Now if we let it run its course not only will high risk people die. Under overloaded circumstances they would not even attempt it, but also those that could have lived will die because providers will be forced to triage and decide who has the best chance of living. Those will get treated and live the rest will not and be made comfortable until death. Unless you have a pandemic with an unusually high death rate this is how most die in pandemics. Keep in mind also that the more cases healthcare workers treat the odds increase that they will be taken down as well, at a certain point even if you can treat everyone if ther are too o few healthcare workers left to do so then it compounds and exponentially increases th ed problems already mentioned. It is not simply about just the illness, that is the minor concern. The logistical crisis is what will kill people and not just the elderly or underlying conditions and it won't be tied to just the infected, people who come down with an unrelated illness or emergency would most likely die as well because of the above.
That being said however, there is a limit to financially how long you can shut everything down and not descend into anarchy because of social collapse either. I do not envy the world/government leaders having to weigh all this. It comes down to do you and what you feel is the best course of action. Most are following guidelines, let's hope it is enough to ward off the really nasty consequences.