Not true, it took them a few months. In this paper published in 2003:
> "Civet cats, a raccoon dog, and a ferret badger in an animal market in Gunagdong, China, were infected with a coronavirus identical to the one that causes SARS in humans save for an extra 29-nucleotide sequence" which demonstrated that these animals had a very close ancestral virus circulating within their populations.
You're mistaking ancestral origin with proximal origin. It took a decade to find the bat virus that infected the civet cats, but the intermediate host responsible for the spillover was found within months.