I don't think Moya belongs to the list.
Moya had an injury, and once recovered his level, he remained a top player from 2002 to till middle 2005. As late as 2008 he was a top 20 player. When you consider that he made the 1997 Australian Open final, that is a very long career performing at a very high level.
Ferrero had chicken pox in early 2004 and never recovered. He wento from consistent top 3 player to being a top 30 floater.
indeed Moya has a very long career
after every serious injury he came back and won some tournements and came back in the top 20, even top 10.
Now his last injury, hip, he has the motivation of playing again and win some matches, but i think he is now 33 years, I think he will not have big results, but that is not due his motivation, but due his age and so