Are you sure that's the case for the 1970-1979 (post A&M-era) CTI albums? Some of them have been reissued on CD as recently as 2008 by Sony and are still for sale on amazon.com, including the first two Deodato albums and the Idris Muhammad album I mentioned previously.
That's what Audio Fidelity has found. The CTI catalog today is controlled by Universal Music Group.