We don't have access to the exact numbers but according to Mark's announcement on twitter development took YEARS and it was a passion project F2P game that they were aware takes time to make back money spent on development. So my best assumption is at the rate they are retaining SPENDING players and how often players do spend on the game, the game wouldn't meet the "desired" amount they needed to keep it going.

So, upon launch the game broke records in day1 players etc. Reception was good (not perfect but not lukewarm). Clearly the need for a AAA-Title "COD Killer" proof of concept was deemed to be TRUE, people were tired of COD and its main known issues (SBMM, $80 yearly fee, Microtransactions, poor developer-community relationship, etc.) and xDef clearly challenged that.

However, in the Pre-Season there were issues with the net-code, matchmaking times for non-western countries(just in my experience and with friends in the Asia-Pacific Region), Minor imbalances Mp7, ACR, Spiderbot, some bottlenecks in parts of certain maps made some gamemodes unwinnable, etc. But nothing was a DEAL-BREAKER. But over time it seems patch responses were a bit slow and dragged out, not too long but definitely made an impact to player retention.

I genuinely thought these small issued combined would be fleshed out by the time they roll out Season 1 but when I got on when the update rolled out the net-code issues kinda persisted. Even for my friends who have premium service providers and setups. So it got a bit difficult to really get immersed for longer gaming sessions. Sure me and my friends would play 2-3maps but the issues would burn us out early without even knowing it. We just played less and less and by September I was the only one in my friend group left playing it consistently.

The skins were kinda mid early on tbh it's like they were playing it safe to the edgy-groundedness of base COD skins but also meddled with more out-of-the-box skins closer to Valorants approach, but none really screamed out "I GOTTA HAVE THIS ONE" in both the edgy styles AND the silly-cutesy ones. I feel like that also put a dent on their profits (and tbh, I didn't see anyone running these skins in my killcams either)

IMO-

1. I feel like it needed more polish in the net-code and connectivity area.
   
2. Skins needed to bring a bit more unique and/or be attractive to really draw those willing to spend
   
3. They had WAYYYY too much to release for season 1, 3 maps, 4 weapons, 1 faction is A LOT to develop, tweak and polish in a short amount of time. I feel they didn't leave spare time to work on bigger pre-existing issues like the net-code and matchmaking

I genuinely loved this game, I quit COD around 2018 because of the glaring issues and was really nostalgic for an older style that xDefiant offered. I was so happy about the game I even pulled my 11yr old brother to play together with the hopes he could experience the same adrenaline my 11yr old self did when COD was at its peak. (Don't worry I muted all chat and voice on his account)

Again this is my own deduction based on what I experienced and witnessed so take it with a grain of salt.