The problem with that is, very few seniors have the neuroplasticity to learn modern video gaming. To be good at it when you're a senior, you have to do it regularly throughout your life. That's not just relative to gaming, that's relative to *everything in life*.
Those who start later in life are categorically worse at a given activity. Look at the top leaderboard or achievements on every single video game older than a decade. Every record is going to be held by someone relatively young.
I also say this as a 39-year-old expert Guitar Hero player who, while being one of the best *publicly active* players of my age, also recognizes that there are a metric fuckton of younger people who literally have the game *woven into their muscle memory*. Some of them started playing the game at a single-digit age - Guitar Hero didn't even *exist* until I was 25 and a half years old. That's a lot of additional neuroplasticity that the newer players have been able to make use of. And even amongst the more god-tier players, the ones who came along in the last few years at a quite young age and have an entire corpus of technique and methodology to build open are the ones making the most gains in accuracy and speed.
Age isn't the *only* reason they're better, of course. I believe I've identified a few physical shortcomings that I either cannot surpass, or will need to work extremely hard to surpass. But the point remains is that, younger people have a greater ability to *learn new things*, whatever they may be, and this is perfectly fine. There's nothing wrong with that.