It already worked fine during the first lockdown last year. At the end we were down to numbers at which tracing contacts and quarantining them worked quite fine for a while. This would have been an acceptable level where people would have been able to do quite a lot of things but not everything. A lot of people overdid it though. Parties, weddings, ... if nothing had ever happened. Unfortunately the response was slow and weak. Now we still deal with the consequences.