AIUI, SARS did cause permanent damage because many people were treated with strong anti-inflammatory drugs that suppress the immune system, despite the ongoing viral infection. These will probably be used against COVID-19 as well, especially given ICU shortages. Hopefully we will gain a better understanding over time of how to properly balance the avoidance of life-threatening damage from the immune response (e.g. due to CRS) with still countering the virus effectively.