There are a LOT more cases than we know, but it's not because doctors and hospitals aren't testing. According to a family member who manages an outpatient office in a local hospital, that's how the coronavirus initially presents. In most people, that's as far as it goes and they recover. The tests are hard to come by, right now, so they try to use them on the extremely ill and to identify cases in areas where they haven't seen it, yet. Like the flu, there's not a whole lot doctors can do beyond treating symptoms and resting - and that's what the self-quarantine and shutdowns are supposed to do.
Personally, I'm okay with that! You couldn't pay me enough to get me to set foot in a hospital or urgent care facility, right now. I wouldn't even accept a house call ... who knows what the doctor's been exposed to?