My own scepticism on his target is mostly about SpaceX developing a soft landing capability in the time frame he's given. I fully expect to see Falcon XX flying by then (X will, IMO, fall by the wayside to a Falcon 9 Heavy variant with a Merlin 2 in each core, only disadvantage is loss of engine out capability), but soft land, particularly of any significant payload is another larger development project at least on the scale of building and flying Merlin 2 and Falcon XX. There is a limit to SpaceX's resources, and I think soft land in ten years goes beyond what they can realistically expect to afford in terms of engineering capacity.
Now, if Blue Origin does everything Bezos is promising I think we have a very interesting possibility for a SpaceX powered Blue Origin developed lander... That said, while NASA seems satisfied I do have big questions about the reasons for Blue Origins' extreme secrecy. That said, I was among the people wondering about SpaceX's true capabilities after the early Falcon 1s all failed.