Taking a look at those milestones really says a lot about the project. It's appears to not in a state of decline per-se, but rather maintenance. I think the world has largely moved on from GTA SA whether we like it or not. There's a tonne of much cooler tech for developers to play with in other mods. There's a tonne of much cooler gameplay mechanics for players in other mods. There's a way more active, motivated and committed teams running those other mods. I think we should be very glad there is still a team here, no matter how small, who still share the passion for the game and want to keep it going. I don't think the excitement or commitment from the MTA Team is the same as what it was 10 years ago. And to be honest, I don't blame them.
What do you gain from a roadmap that has a few cool pie-in-the-sky features, but mostly details small improvements, maintenance and platform upkeep? Because to be honest, that's what the roadmap would likely be. Small iterative fixes and improvements are worthy of talking about, I agree. It comes back to this team are doing this in their free time. I would rather they spend their time on MTA on keeping it alive, rather than busywork like updating superfluous roadmaps.