Platinum for life is the answer I've been given, although like everything else in life, I am sure this too may change.
I truly hope CO remembers the Infinite Elites who stuck with them through the long Lorenzo years, Peanuts Fares and Continental Lite debacles!
BTW, I also truly hope that IF CO ever does plan to eliminate the infinite elite, they give us a year or two's warning. In 1999, for instance, I will come up about two segments short of earning Platinum again. Since I'm Inifinite, it is of no consequence. However, if I knew the program was coming to an end, I easily could have changed a few trips from nonstops to add the segments.