Why would our growth curve turn into the next Italy or Spain when it was nothing like that to begin with?
Averages hide tremendous variability. In the US, some specific areas are "Italy"; others are just fine. The key is going to be how quickly we can shut down new outbreaks before they get out of control in specific hotspots. We here in the US are behind that curve; sounds like Australia has much better systems in place.
I think the fundamental problem is that a huge part of the general public has trouble conceiving what exponential growth actually means. This disease can hide for up to 14 days before you even know you're sick -- average incubation period I think is 5-6 days -- and yet you can be infecting others that whole time. When you're in the peak of it, cases tend to double every 3 days or so. That means that from the time you get exposed and start contaminating people to the time you (on average) will even know you're sick, the number of cases in your area could quadruple. That's why/how/when hospitals get overwhelmed and the death rate skyrockets. I saw one analysis that says acting two weeks earlier cuts the death rate of an outbreak by 90%, and one week earlier by 60%. That's just a projection, of course; we can't really know. But it illustrates how quickly this thing goes from zero to epidemic. So unless/until we get some sort of early testing, the only way to control the spread is to impose serious restrictions long before most people think they are needed, and keep them in place long after most people think everything's ok.
With respect to masks:
https://www.youtube.com/watch?v=kYJvU81DKgk. It's not about protecting yourself; it's about protecting other people from what you may have but not even know yet. No, it's not perfect; we all have to breathe, and that air needs to go somewhere. But wearing a mask of any sort limits how far you project droplets when you cough of sneeze, which will protect people a couple feet away from you. In addition, there is suggestive evidence that the severity of the disease may be affected by virus load -- that is, that someone who has passing contact with the virus may get a less severe version than someone who is inundated with the little buggers. So if you end up standing close to someone for a few minutes, you're probably better off if they have a mask on even if they do pass it on, because the smaller exposure is more likely to result in a mild illness.
I think with all of these decisions, you need to weigh the potential benefits (magnitude of benefits x degree of certainty that you're right and it's actually going to happen) against the burden involved. There is clearly a huge burden in shutting down the economy. OTOH, the burden of putting a damn bandana across your face to protect your friends and neighbors is pretty small.
