This is disingenous. The last SpaceX rocket successfully returned from suborbital flight onto the target landing site. They just underestimated the amount of hydraulic fluid needed to make a proper landing (but then again, they hit the barge anyway!). It's basicaly a 99% success with a minor error that was found and will be corrected.

Stupid failures always happen, but at this point we can definitely assume that yes, they have a reusable stage.