The view you are suggesting works, in the sense that it is logically consistent. However, I very much doubt that this is the calculation that went through very

The view you are suggesting works, in the sense that it is logically consistent. However, I very much doubt that this is the calculation that went through very many people's heads, say, 3 weeks ago. I think proof of this is that in all places that have substantial outbreaks, containment measures are getting heavier and heavier with increasing numbers of cases. If that's what you were going to do anyway, then the sum cost (in money, time, human effort) would have been lower if you had started earlier. This is because exponential growth with a factor of 1.33 is still manageable if you have 10 cases, but turns into an overwhelming tsunami if you have 10000.