The most profound will be the overall drop in per capita GDP, reinforced by likely lowered life expectancy, inadequate treatment of screening and other diseases, delayed or abandoned vaccinations for polio, measles and diphtheria, mental health problems and self-harm, and adverse effects on educational outcomes.
All are what an economist would call the opportunity cost of closing much of the economy and building a government debt mountain for future generations that has ballooned from $57 billion in 2019 to an estimated $200b in 2023. (This has since been revised downward to a debt of $170b or 40% of GDP.)
Behavioural economics explains the failure to incorporate human response factors into the epidemiological models on which the lockdowns were based. Humans tend to focus on losses that are immediately in front of them rather than those that are more diffuse and dispersed in the background, even when they are larger.