The core problem with the ‘lock down’ strategy is that only works if everyone is single. Everyone is not single. Most people cohabitate in groups. If one individual from a group lock down becomes infected they then infect the rest of the group, causing multiple infections. Then others from the group typically will do the same in other groups. Most health-care workers for instance live with their families and end up infecting them because their families are locked down and so on and so forth Lock downs do not work and Italy and Spain are the best examples. The United States and especially New York are about to become another example. Wearing a mask at all times is the only true detriment to this virus and the quicker Americans start doing that the better off they will be.
The relations outside groups are more rare than inside. You might infect a very limited number of people inside your group and then if they pract8ce isolation it won’t spread further.
Especially in the overcrowded tenements that the immigrant communities live in in New York. They are breeding grounds for any air borne diseases, not just coronavirus.