Sorry I flubbed that -- I meant what are now called chiplets interconnected and packaged together used to be called MCMs. A chip was always a single piece of silicon (aka die), so chiplets used to just be called chips. There was never any rule that chips in an MCM were "standalone" or functional by themselves like some seem to be saying, in fact earlier computers used multiple chips for subsystems of a single CPU (https://en.wikipedia.org/wiki/POWER2 this thing had individual chips for IFU, LSU, ALU, FPU, and D$). There was never any rule that MCMs were not low latency or high bandwidth or must have a particular type of interconnect or packaging substrate.

Advances in technology and changing economics always shifts things around so maybe chiplets are viable for different things or will make sense for smaller production runs etc., but that doesn't make them fundamentally different that would make them not classified as an MCM like the article seems to suggest. It literally is just the same thing as it always was, multiple chips packaged up together with something that is not a standard PCB but is generally more specialized and higher performing.