Every new elite top tier comes into existence the moment I reach the prior top elite tier. Ergo, there's something above GS in the works, now that GS is the old 1K...
My guess is GS came into being in 2000, my first 1K year!
1K came in I believe in 1993, which was my first year as a top-tier Premier Executive (courtesy of a couple of unplanned trips to SE Asia as a student and a imiscredit that went into the wrong year). So it's a thing.