That is the money quote on the cancellation of the DDG-1000 at 2 ships. It appears that while it could technically carry Standard missiles in its vertical launchers, it could not guide the missiles, and would have had to rely on another ship to do so:

However, in the current program of record, the DDG-1000 cannot perform area air defense; specifically, it cannot successfully employ the Standard Missile-2 (SM-2), SM-3 or SM-6, and is incapable of conducting Ballistic Missile Defense.

(emphasis mine)

No Standard missile capability, so it’s just point defense (Sea Sparrow), and ground attack. As Galrahn notes, that makes it a more expensive variant of the Arsenal Ship canceled in the late 1990s, despite the fact that the navy very strongly implied, through the DDG designation (the “G” standing for guided missile air defense), and through its expansive descriptions of the sensor suite, that the ship could provide air defense.

It appears that the threats from new generations of anti-ship missiles will have the navy buying more Burke class DDGs, though some DDG-1000 tech would make into the new build destroyers, primarily electric drives and the new gun, along with systems to allow for a reduced crew size.