Following IBM's lead?
In early 2000, an OS update, caused by a hardware update (y'all know the drill) finally killed off support for IBM 1401 emulation on a System/360 descendant. The emulator was introduced in the mid 1960s to ease software migration, and the last IBM 1401 rolled off the assembly line in 1974 (IIRC). So, 25 years of IE is not exactly a match for 35 years of 1401 emulation, but not bad for these days when "What kind of loser expects software over 3 years old to work?"