No.
Halo meant something very important, to become the first FPS with proper controls in console, and later a great online MP. It was something very different and innovative, became iconic of Xbox, and there wasn't anything like that back then.
Starfield still didn't prove anything. As of now, it only seems a AAA version of No Man's Sky, or Skyrim's in space (for this gen), or Bethesda's Mass Effect (for this gen). And having previous stuff from Bethesda like the releases of Redfall, Fallout 76 and Elder Scroll's online I'd wait at least until its release to see if it's going to be a great game.
I think the most imporatant Xbox game since Halo was Gears of War, and that Starfield won't be more important than Gears was. I think it will only be important for the MS/Bethesda fans, or at least part of them in case it turns out to be really good. Which is likely but I'm not 100% sold.