It is not really possible to do a FULL or COMPLETE lockdown, because life continues, ie;
Babies get born, people have heart attacks, or accidents at home, that require medical attention - eg fall down the stairs and break a leg, etc;
People need to shop for food, which require shop workers, deliveries, etc
So, if medical attention continues, and shopping continues, this requires contact with other people, thus transmitting the virus.
(Note I have omitted the continual medical attention, some of which was postponed, such as cancer diagnoses, mammograms, physiotherapy treatment, etc)
Secondly, some people live in larger households, where people become infected one after the other, so a household with 10 people could remain infected for maybe 10 weeks. (Obviously I doubt this would happen, as some people would be infected together, but it shows how a 4 week lockdown does not really work)
We had a 3 month lockdown in March, which did not work. There's no reason to think it would work this time.
The economic cost of the lockdown will be felt for many years. If you think it has not affected you, then you are fortunate, but this is because the cost will be born in the future, and yes, it will affect everyone.
Meanwhile, children's education suffered, people's mental health suffered, due to the isolation, etc