One goal for disease likely to cause pandemics is ultimately to create better treatments for those already infected. There’s a long lag between a vaccine being designed and scaling production and distribution to actually protect people. That means there’s going to be a lot of people infected in an outbreak, including many vaccinated people.
Take antimicrobial resistance, you need to understand how microbes gain resistance by actually creating resistant bacteria/fungi etc before you can develop efficient countermeasures.
With COVID there was a lot of confusion around using masks and disinfecting public spaces in the early days. A better model of the disease could have been really useful both in the early days and how people responded to mixed messages.