I imagine the profit margins and sales were low compared to Noiseindustry’s FXFactory. I suspect they though FXCentral would generate ongoing revenue. With the release of RedGiant Universe, I don’t doubt Genarts saw no way to make it a go in this market.
Tangential but I’ve heard BorisFX is not particularly happy with Boris Continuum Complete for FCPX as well.
I honestly can’t imagine full Sapphire being released for FCPX unless Genarts is implying a major price drop.