The Ektaflex and Instant Film groups were both part of the Diffusion Transfer Community at Kodak and we worked closely together since both products used the same dye-releaser technology. I did quite a bit of Ektaflex testing (including making prints in my basement with the temperature about 65 degrees). The reason for it's demise was the dye-releaser technology. The dye-releasers were expensive and when Kodak lost the Polaroid lawsuit, the major use of the dye-releasers was gone and the expense/volume didn't justify further manufacture. Thus Ektaflex was discontinued.
Fuji obtained the dye-releaser technology in a patent trade and used it in their Pictrography printers (and of course, Instax film).