Honestly, no one knows how long the economy can survive a lock down.
100% agree. A reporter on the BBC coined the phrase "existential debate" meaning - bluntly - the cost of immediate fatality versus the cost of forthcoming fataility owing to socio-economic collapse. Some of the well-intentioned financial measures to support business in a service economy are not going to work. No rational business leader is going to borrrow money to sustain a business which has no future. Assuming this goes on for just a few more months, in the coming years the majority of the economically active part of the population will concerned with paying their mortgage and bills and putting food on the table. There will be squat for the "luxury" part of the market place which means devastation from lack of demand in the leisure and travel sectors, which form a sizeable chunk of any service economy. Not just airlines, hotels, clubs, pubs, restaraunts, any form of tourist attraction etc etc.
Governments will know this they are not dumb. They will be frantically searching for two solutions. 1. More realistic (yet still some how "affordable") business support measure, to eek out business survivability a few more months. 2. An exit strategy that gets people out of their homes and back to work. If that sounds like a statement of the obvious, maybe the implied bit is that the exit strategy is going to have to accept a level of immediate fatality higher than people might expect. In other words, I doubt we will remain locked down until this virus if a) fully under control b) we have herd immunity c) we have a vaccine. I think we will have to be out and about before any of those things happen.