If it's lack of personal investment informing your decision to quit developing for the game, that's something I feel nobody could fault you for these days, given your history with the UT community and the body of work you'd be leaving behind. After all, one can only continue labouring on something for so long while (presumably) not deriving any personal benefit or satisfaction from it before eventually taking stock, reassessing things and deciding to stop. While understandable and inevitable for everyone in game modding, it's definitely also a sad turn of events, especially considering that at this point it's hard to even tell whom all that leaves behind as still actively, and competently, creating original UScript content for UT2004/ONS. I'm talking about people able to experiment and innovate in directions still very much unexplored in ONS, such as, say, movable objectives, objective-prioritized scoreboard rearrangement, infowar, bugging/tracking and comms jamming, composite vehicles, destroyable wheels, shield disruption, net-enabled KarmaThing/NetKActor equivalents for KBSJoint and KHinge, to list just a few of the concepts I've been looking into for years now personally.
Now, obviously the question of whether ongoing development for ONS should be regarded as foolhardy or still a worthwhile goal in these twilight days of UT is something best left up to each community member to decide on their own, but my message here to those few still concerned with the bigger picture is that yes, there does remain plenty of territory left to explore in ONS game design, should anyone possess the ability, knowledge and, most importantly, the desire to press on, disregarding the usual siren calls of simplistic n' derivative, arms race-oriented modding. I honestly can't say if that's the sort of challenge you might consider as the exceptional "something" that could bring you back with renewed interest or not nowadays. To my mind, however,
that is the thrilling promise UT2004's ONS can still offer its modding community, and IMO it's definitely a cut above and beyond anything subsequent iterations in the UT franchise have been able to deliver on (so far, anyway), so that's where the destination continues to lie for me, however limited my own dev skillset may be and unlikely the odds I'll get there.
If modding no longer holds much (inspirational?) value for you, though, after sticking with it for over 15 years (!), that's something I absolutely can appreciate and respect, and I'd gladly still be among the first to line up to thank you for all your contributions to this game[type], as well as wish you an enjoyable, stress-free time with your subsequent projects. I'd also not mind admitting to some disheartened astonishment by the complete lack of reaction from this community, or any other, after two full days since your announcement of intending to hang up your UT modding hat, considering how much most ONS players, and beyond, have benefited from Wormbo's work over the past decade. While I'm more inclined to attribute this omission to the busy nature of this week, causing the post to fly below most people's radar, than to apathy or indifference - especially recalling how many CEONSS members and staff have in the past expressed their appreciation for the Worm - this turn of events has still managed to earn itself a trademarked Peg
:/.
Oh, and,
Wormbo wrote:[...]The only FPS game I played recently is Mass Effect (the first one, I still don't trust Origin enough to let it even near my PC)[...]
Speaking as someone with a severe distaste for any kinda publisher's DRM-infested platform being installed on my machines, I can't blame you one bit for keeping away from it (or Uplay or any other equivalent, Steam included), even if a game they released might be worth trying out. Besides, PC games getting cracked is just as reliable as entropic increase, both to legit purchasers and file sharers alike

.