I think it had more to do with the problems they experienced with process architecture. To keep making things smaller and faster and use less power, they relied on die shrinks. The 750 ti has been the go to sff card for nearly 3 years now because they were stuck on the 28 nm process. Because of the problems and delays with 22/20 nm they wound up skipping it and went directly to 16/14. In the meantime they did keep offering new designs, but they generally wound up being larger, hotter, and more power hungry cards unsuitable for sff.
MSI has already announced some low profile 1050 series cards. So far I haven't heard anything about any low profile 460's, but there's a bunch of people clamoring for them.