Yes, a vaccine was developed, but for SARS, a different type of coronavirus.
Sure, it would've been nice to have a vaccine for another coronavirus on deck, but it still would've needed testing trials for its efficacy on COVID-19.
This is where I wish journalists did a better job of explaining aspects of science, especially in cases like this. Details matter.
There is already at least once vaccine developed; it is in the initial phase of testing on humans, and if it works/no bad side effects, it'll progress to a larger sample size.
Generally, vaccines can be made relatively quickly. It's the testing that takes a while.