1. We could invent a vaccine and discover that COVID mutates slowly enough that we get long term immunity. After mass vaccination in rich countries, the problem is basically solved after 1-2 years and life can go back to what it was in 2019. However, after 2 years of changed consumer habits and a set of companies and supply chains that will naturally adapt to the situation in the interim, the new normal might be significantly different than the old normal. Governments and international trade will have been changed. Investments in automation and telework will have been made. Some changes will be permanent. Like with WW2, 9/11 or the Great Recession, the ripples of causality will spread out for decades.
2. We could realize that the virus mutates fast enough that even with vaccines, we have a new endemic virus, possibly resembling the prevalence of the flu, but much more deadly. COVID will be one of the leading causes of death, up along with heart disease and cancer. People accept this increase in mortality and accept shortened lifespans. After several years of adjusting to the new reality, people start to just live with it. Some common activities completely lose their appeal due to the increased risk, such as theaters, concerts, travel, public transportation, and open offices.
3. We are unable to vaccinate against the virus, but continue aggressive measures to keep it from spreading a much as possible. We accept a new form of digital surveillance state that keeps us the goldilocks amount of isolated. We accept the new reality of algorithms determining our ability to live, work, and socialize. Life is increasingly lived digitally and in VR.
I think it's important to consider these possibilities because of the Normalcy Bias. The best way to overcome it to to seriously consider that tomorrow will not at all be like today. https://en.wikipedia.org/wiki/Normalcy_bias