There will be lessons learnt from this, and I think lock downs will be looked at very differently next time around. Maybe not done away with, but certainly very differently.No countries can afford an extended shutdown. But it probably wouldn't work anyway. People have to go out to get food and other supplies. People are still going to need doctors and dentists. If it is true that you can be infectious for while before showing any symptoms it is still going to spread, but maybe a bit slower.
Ultimately there is a huge cost - the economy, people's savings, children's education, people's mental health, etc.
Its also difficult to peg a lockdown level on a novel virus until you clearly understand whether you're dealing with a bad flu or the end of mankind...