That’s quite a number. A recent rumor has it that Blizzard accidentally leaked World of Warcraft's subscriber count. According to the data, there were 3.2 million active subscribers as of 2014 (that’s when Battle for Azeroth launched). Then the numbers shrunk to 1.7 million players worldwide, excluding Asia.
The leak, however, have to be taken with a grain of salt, as its source cannot be reached. The data was published on the official Twitter account of WeakAuras, a popular WoW addon. The tweet stated that Blizzard’s own API – develop.battle.net – was in fact leaking “player subscription end dates.” But tweets that followed revealed that the “[original] post with those findings has been deleted.” Furthermore, Blizzard itself contacted WeakAuras and said explicitly that the data was wrong. Currently, we are at the point where WeakAuras says things like, “Just because something ended up being written on the internet, does not mean it's true,” so the data should not necessarily be trusted.
Blizzard gave up sharing subscription count back in 2015, a year after Battle for Azeroth made its debut. When the addon came around, there were 10 million players enjoying WoW simultaneously. Back in August, the game reached $161 million in revenue, rendering itself the second biggest PC title when it comes to popularity, losing only to Dungeon Fighter Online. 3.2 million is still quite a number, then – but it also pales in comparison to the good ol’ days of peak popularity.