Wait what? Where are you getting the 10k players thing from? I'm totally with you that it experienced a huge drop off (most games do naturally but Blizzard games pedigree was longevity and value) but that seems dubious. Is it that old XFire source? It's a good indicator but a poor value to use as an actual statistic.
Playing: XCOM 2, Diablo 3 Watching: American Crime, Regression