Hard work and dedication will make anyone good at anything - no-one disputes this. But Syed wants to apply this to the elite level as well. The elite level is where outliers live on an everyday basis
The studies he cites goes the wrong way to draw the conclusion that he wants to draw - it's not about saying table tennis players have super quick reflexes that apply generally it's that some people have super quick reflexes of a type that apply to table tennis. So, whilst Table Tennis players' 'quick reflexes' are clearly trained for the specific situation of Table Tennis rather than being the results of having 'talented' generalist quick reflexes there will be, in the pool of all of humanity, people who's natural bio-mechanic disposition makes them have Table Tennis appropriate quick-reflexes. So if that person applies hard work and dedication to Table Tennis then they will be better than someone without the bio-mechanical advantage who puts in the same hard work and dedication. But if they apply hard work and dedication to another discipline that require fast reflexes they won't be any better as their 'talent' doesn't apply.
I follow rugby, rugby is littered with players who were really good but who's body could not take the strain of the training and broke down through the effort. Clearly hard work and dedication alone was not enough for them - they needed a body that could respond favorably to the punishment they were taking.