Why should we wait 20 days for things to get terrible before going to quarantines and lock down? Surely China and Italy have shown us our future.
I partly think the problem is political. If you quarantine and the virus is controlled, then it looks like you panicked over nothing, because you took this huge reaction and nothing much happened. However, if you wait till it's sufficiently bad and then you quarantine everyone will understand what you did, and later, you may get praised for your decisive leadership in a time of struggle.
What I mostly wish is that citizens could throw some sort of flag now to say "This crisis is being poorly handled. If this goes badly, let's have a review, figure out why, and correct the problem once this is settled."