Surely at some point people will wake up to what's going on and say "Enough!"?
Politically it's very difficult for the government to say "Sorry, nothing we can do. Good luck if you catch it."
Quite understandably, nobody wants to make that call, so we're in a situation where essentially the government is trying to buy time while hoping for a miracle (i.e. much quicker than expected progress towards a vaccine and/or a drug therapy that's proven to be effective.) People will only tolerate lockdown measures for a finite (and short) period of time.