When Marathon launched, it didn't really cause a massive splash, as Bungie's extraction shooter brought in decent player figures but nothing earth-shaking. The main concern seemed to be how the game was mostly being played by PC audiences, and yet despite this being the situation, it never even cracked 100,000 concurrent players at debut. For reference, The Binding of Isaac smashed such a record recently basically for the fun of it.
Still, for the sake of Marathon, as long as the game had a healthy and consistent player base it would likely be classed as stable and safe, but this hasn't exactly formed, at least when looking at the Steam figures.
Following launch, the Steam player count as dictated by SteamDB, has been consistently fading, with a jump occurring when Season 2 debuted at the start of June. However, this jump was short-lived, and the latest data shows that as of this week, on two separate occasions Marathon has slipped beneath 1,000 concurrent players on Steam, with the lowest low being 641 players on July 7 and the other being 822 players on July 9.
The other main point of concern is how the average player count seems to be 4,000 players, with a 24-hour peak of 7,547. But the data also shows the player count is slowly dropping off too...
Again, this issue is compounded if the former report is accurate that the majority of sold Marathon copies are in fact on PC, as this would then suggest the console player figures are around a third of what Steam shows. Either way, it's not a good look for Bungie's extraction shooter.