For Intel's chips, it was added as part of SSE4.2 in the original first-generation Core architecture, codenamed Nehalem. In AMD's processors, it's included in SSE4a, first used in Phenom, Athlon, and Sempron CPUs based on the K10 architecture. These architectures date back to 2008 and 2007, respectively.
Of course they probably could have avoided it, but a 15 year old PC is as close to ewaste as it gets. Even if you could run Linux on it, a modern smartwatch probably has more computing power, let alone a smartphone or raspberry pi. The main use could be as a space heater.