Consider that in the US testing has barely started and even then there are a ton pre-conditions to get tested. Any “scary growth curve” of any absolute number you see is almost certainly a reflection of how much tests are being done. More tests means more confirmed results which means a nice scary looking curve.

If you start with a hypothesis that this virus is already in widespread circulation and possibly has been for a while (which is the simplest explanation, mind you), odds are good many people already had it or have it right now.

Only way to prove/disprove if it is widespread is by testing a random sample of the entire population. Something we aren’t doing in the US.