We could have locked down the vulnerable (60+ and those with pre-existing conditions), and anyone with a temperature, focused our healthcare efforts on them and let everyone else go about their business with more caution (masks + hand washing).

We would have built societal (cows are a herd, humans are a society) immunity by this point and could slowly return to normal for the at-risk crowd.

As it stands, we haven't built up any social immunity and will have to wait over a year for a vaccine which, by definition, we will not know the long term effects of.