In the overwhelming number of cases, an absence of improvement of rating over years is due to indifference, laziness, or ignorance of the fact that you can't improve without learning. It is not due to lack of talent.
A peculiarity in the USA is that quite many people are under the wrong impression that (heridetary) talent would be more important than work, so they blame lack of (own) talent for misfortune in chess...
I absolutely agree. I was for example really bad at math in school but with hard work I was able to get really good grades in math in college.
Actually it wasn't even hard work. I practiced and learned on a daily basis. When I wrote the exam I was amazed by how "easy" it was.
The same or similar thing happens in duplicate bridge. Some players make the same mistakes over and over again and are not interested in playing a stronger game.
But they love the game anyway. And there is nothing wrong with that.
Same thing happens in poker to a degree...[except with poker they lose money]