Edit: I enjoyed the post, but his point turns out to be a relatively narrow one:
The other headline from the replication is that the predictive ability of the marshmallow test disappears with controls. That is, if you account for the children’s socioeconomic status [etc...], the marshmallow test does not provide any further information about that future achievement. It’s no surprise that controls of this nature do this. It simply suggests that the controls are better predictors. The original claim was not that the marshmallow test was the best or only predictor.
Such a defense of the original claim makes sense in an academic context but doesn't touch on why the marshmallow study made it into pop culture in the first place. That was because of what it seemed to suggest about character and self-control. The new study puts quite a different spin on that, as Collins agrees:
What is called into question are the implications that have been drawn from the marshmallow test studies.
The fact that those implications weren't part of Shoda, Mischel, and Peake's original study is good to know, but not the most important thing for non-specialists.