Having been able to adapt previous work from SARS and MERS, coupled with the massive funding and movement of researchers and staff from other research areas, it's not so outlandish.
Think of it this way......it only took four years to develop a vaccine for Mumps and that was achieved in 1967. With our increased medical and scientific knowledge, superior technology, and with so many resources thrown at it, it's easy to see how such rapid progress was made in 2020.
