Wall Street used to worship what we would call "quants". These PhD's would promise the universe, and very frequently, they delivered. Until they didn't. Because, from time to time, the underlying assumptions behind their models would be violated. It's something the rest of us like to call the "real world".
You can model stuff and draw conclusions, but ultimately, your results must match the real world. And in this case, what we see a lot of are superspreaders. People who, to take one obvious example, might work as a flight attendant. Or a roving home health specialist. Whatever. The model isn't as robust as one might think, and we don't have time to test all of this out.
Second issue. If you restrict everyone more or less to their home for a period of time, fine. You've slowed the virus. You better have that vaccine ready, or else a month or two later when you let everyone out of their cages, and they commence to drinking and fucking and all those things humans do, the disease comes back in a massive way.
The goal here is herd immunity.