Okay, but having an economy in the modern world is a necessity also. No one suggests getting rid of cars because it's impractical. Just like it isn't practical to keep the economy shut down eventually. If it's a short term tactic for a few months, that's one thing, but what if it ends up stretching out into years?
Mind you, I'm on the side of social distancing. But I can still see arguments for both sides. What if this just ends up prolonging the inevitable? People have talked about a modified distancing where we isolate the elderly and high risk and send the younger, healthier folks out to work and develop herd immunity. As a country, we've decided on this social distancing strategy, so we need to give it our best effort to give it a chance to work. Time will tell if we're doing the right thing, hopefully, although I doubt that everyone will agree on that, regardless.
Right now there's just too many variables to implement what you suggested, which in a perfect setting would naturally yield positive results, that I do agree.
As for the social distancing, the initiation of a lockdown is in fact a forced measure taken by many governments because things were getting out of control or beyond their control - it was an act of last resort since this virus is new and with unknown lethality to individual nations (it affects different people differently in different demographics).
Some other countries didn't initiate a lockdown, for example Singapore, Germany, Sweden...etc, because they were able to generally contain and control it.
As for the virus itself, it's likely to be a yearly affair, right now all that humanity could do is mitigation, an act of buying time.
You need to understand that a very big chuck of humanity can't accept deaths by the millions of their love ones, even if they are old, more so when taken before their time. For them, money they can always find but once a love one is lost its forever.