Interesting. I find the main point of concentration meditation to be to disregard non-relevant stimuli (ie not my breath) and continually bring back attention to the predetermined focus point. This could be building the strength of the executive function in the meditator's brain. There is already an obvious benefit to a regular meditation practice, as evidence by the growing amounts of research into its effects.
Yeah! There's strong evidence to support gray matter increase in the prefrontal cortex, which would also support executive function improvement.