I think you're overlooking the idea that "lockdowns", as we know them, do little other than impose massive costs and anxieties on society, while failing to achieve their main objective i.e. complete immobilization and eradication.

So you end up with all the costs of the policy with little upside because the dynamics of spread seem very heterogeneous, mass-spread seems to happen in relatively few people in very particular scenarios (crowded indoor areas - notice that lockdown ends up pushing the entire society, especially the least healthy and most vulnerable, indoors).