We can't stay in lockdown to protect a small number of vulnerable misses a huge problem relating to the economy.
International trade.
Whilst we might be happy to let coronavirus run riot and burn through our entire population, that's certainly not true internationally.
We risk being cut off as international pryors if we don't make proper efforts to control the spread.
Because other countries do care about their vulnerable more than we appear to.
France has previously made noises about closing the Channel Tunnel if we don't get a grip of the situation because it had the potential to undermine the effectiveness of their lockdown.
Do we really want to end up in a position of begging for (expensive) food parcels from Don? And being unable to export to many other countries because of concerns about the virus?
How damaging to the economy do we think this would be? Sure we'd have a nice enemy to blame and someone heroically saving us, but it wouldn't exactly be in the best interests of the healthy workers and our economy in general to put it mildly