first we need to establish what side the burden of proof is on to provide the data that quarantining a healthy population will stop the spread of the disease. It's not the populations responsibility to provide evidence it doesnt work, it lies squarely on the side that says we need to invoke an action that is borderline unconstitutional and deprive 328 million people of life and liberty to avoid further spread. Just like the court system has to provide evidence of guilt before stripping an indidvivual of their freedom so is the same in this case. There has never been a time in history of the united states where a healthy population has had to face quarantine, so at the end of the day its a wild guess on the part of the "experts" and as you said "based on feelings".
You are correct about one thing which is we will see what kind of effect it has had. My money is on Sweden
. You will see a massive amount of initial deaths and it will taper off and the population will build herd immunity. Reports are the general population there have a 25-30% immunity rate. The swedes introduced the world to greta thunberg, this is their shot at redemption!
You mentioned new zealand. A couple of things regarding that example....for starters its a small secluded island with no neighbors. That situation doesnt apply to 90% of the world. They dont risk people just casually walking over their borders. Secondly, the first case of the virus was in end of February. They were able to isolate the patient. In other countries you will be able to facilitate contact tracing via different methods, but not in the united states. I'm willing to bet you wont get more than 20% of the population willing to download the app that is proposed.
Lastly, I would like to point out your stance on crippling the healthcare system. If that is your presepective then I would suggest isolating regions based on hospital utilization. It would have been a better alternative to a complete lockdown of pretty much the whole country. You would still have fellow countrymen employed and building herd immunity in the process.