FCP was never the only solution in the pro video editing market. Avid has been the traditional choice since the mid-'90s, but FCP was encroaching.

Unfortunately the botched introduction of FCP X sent Apple back a decade in this market. FCP X was too different from 7, and it didn't even support many of the workflows that pros needed. Since users had to learn new software anyway, a lot of editors went to Avid or Adobe (Premiere is quite good nowadays).