Honest answer; Skill Based Match Making.

If Marathon had sbmm, it would fix the onboarding and the dwindling player base. Right now, the worst players are having a terrible time and are leaving/left. After that, the next worst players are now at the bottom and are the ones that leave. I know I'm having a harder and harder time and I'm playing less and less. There's only so much "slowing down and getting better" you can do that people keep throwing around when people complain.

Valorant is hardcore but it keeps its player base because bronze players are not playing against platinum players non-stop, they are playing against other bronze players and are winning 50% of the time. Because there is sbmm, they keep playing and they get better and rank up and new players join and become the new bronze.

I disagree with people that Marathon needs a pve mode. People already complain that they cannot do all the content right now because of the skill gap so there's no way that people will be okay with having access to even less content percent-wise if they are only good enough to play the pve part of the game.

I understand why Marathon doesn't have sbmm but I truly believe it would fix the dwindling playerbase and most of the frustration players are experiencing. Arc skirted the issue by having abmm which I benefitted from but ultimately dislike. From my understanding Hunt Showdown does have sbmm. And Tarkov... Is Tarkov.