Too late for that now. You can blame the Obama administration, lifer-congress critters, and lifer Federal bureaucrats for failing to reform regulations and processes after the MERS outbreak -- that is what South Korea did. It was no magic that they were better prepared than most countries. They made the necessary changes years ago.
Bogging down the Trump Administration with constant hoaxes and impeachment garbage probably didn't help us either.
Testing can be for surveillance or diagnostics. Surveillance testing is aimed at reducing the spread of infection or monitoring the spread of infection. Diagnostic testing is to identify infection for treatment purposes.
The treatment for covid-19 is self-isolation unless severe symptoms develop. The same as the FLU, you don't need a test to figure out what to do.
Note, I am not suggesting that Covid-19 is "just the flu." I am suggesting that the treatment and preventative measures are the same as for the flu, until a cure or other treatments are discovered.
Personally, I think part of what SK did was, by having drive-thru testing, EVERYBODY was made keenly aware of the problem, and reacted accordingly.
I have pretty good faith in our ability to self-isolate and minimize transmission. Except people were not trustworthy, so we needed to ban big gatherings and stuff. I hope they can refrain from shutting down gyms or closing restaurants. Restaurants can to most of their sales with carry-out, and gyms (the good ones) are some of the cleanest places you can find short of hospitals (and don’t have the problem of a constant stream of sick people).