That set of numbers should be put into proper context. These are not “reliable monthly sub” numbers.
It was a pretty significant ISK giveaway, along with other rewards, run at a time when a 30-day sub would also allow an account to vote in the annual CSM elections. I know of at least a couple dozen alts that were subbed for one month only to catch the ISK/vote combo (2 of them were mine).
This means that at a probable “peak” sub-count number, CCP is making a little over a million dollars a month from subs. Given the financial issues that CCP has experienced in the past, I would consider that “emergency action” range of financing.
A quick look at PCU numbers shows that EVE is at it’s lowest login levels ever, even lower than the panic-level numbers they hit in 2016, causing them to open the doors to F2P, or the Blackout disaster of 2019.
With any luck this is a combo of reduced Covid restrictions giving people more options in their leisure time, plus war-end exhaustion, and players checking out recent game releases (New World, WoW etc.). It could also mean that increasing numbers of players are simply not on-board with EVE’s direction over the past few years and are voting with their feet.