Two things make this virus particularly insidious. One is the lag time between contagiousness and symptoms - up to 5 days or more. The other is the fact that it does affect older people more than younger (although 38% of the hospitalized are between 20 and 55). I remember what it was like to be young - thought I would live forever. So the young are crowding the beaches and living it up while spreading death.
Cities and states shutting down doesn't do any good right now. If the strategy is self containment so virus runs its course, then it will need 100% cooperation across the United States. Short of that, it does singular cities no good because a positive carrier can still come in and the spread starts all over again. Here are the things that need to happen:
1. 100% testing to identify who has the virus and who doesn't and make the ones that are positive self contain for 14-21 days and retest afterwards to make sure they are "clean". There's a reason why South Korea emphasized testing on a broad scale as soon as they identified a carrier. They also did contamination tracing with all positive carriers to see who else could have been infected.
2. 100% self containment in all cities across the United States (see paragraph intro). Will also require shutting down the borders until a high percentage of the world population is infection free. This is probably the one that does the most damage to not only our economy, but the world's economy.
These are other options that are the "nuclear scenario"
1. Let the virus run its course and deal with the consequences. Right now, the highest guarantee of immunity from the virus is to catch it and deal with it. Of course, the "herd immunization" theory would lead to deaths on a massive scale...is the world willing to live with that? Can the world deal and all the hospitals deal with the fallout?
2. Quarantine the elderly, the immuno compromised, the sick, and the children. Let everyone else catch it on purpose and let the virus run its course. Of course, there's a lot of fallout here as the scenario above, but less than the first one (in theory).
Short of someone finding a magic bullet (the cure), there are no easy answers. Given how many people there are in the world, quarantines mean absolutely nothing unless everyone in the world buys into quarantines and self containment. Cities will be able to temporarily "flatten the curve" and even have a descending cycle, but it will inevitably rise again because you're trying to catch a school of minnows in the ocean with a guppy net.
If you studied the Spanish flu, they were able to lower the infection rate at first, but it also flared up again later in the year. That's all we're doing right now.