They’re only a good idea if you have an exit strategy that is feasible.

We didn’t have one. We didn’t even seem to have an infeasible strategy for a long time! And as a consequence, lockdown became performative rather than strategic.

If we’d have locked down hard enough, and if infection had fully died away without meaningful transmission to animals, then we’d have been able to unlock.

But we didn’t lock down hard, and probably we realistically could not have done so.