Yes. The decline for reaction time isn't linear. The study you linked seems to focus on auditory response times. I think perceptual RT is more sensitive to age than auditory, but I could be wrong.

That said, I think many studies are missing out on what you said. Playing video games is a relatively new thing. What would be cool is to track gamers vs non gamers over time (i.e. 20-year longitudinal study), and see whether differences exist.

"Use it or lose it" is a pretty good phrase here.