Scribbler covered some of the ways in which you can define talent, which was what I wanted to expand upon.
There are definitions of talent you have to look at, and what you can make up for and not. I am terribly unathletic, and am constantly working to try to fix that. Nerve damage on my left side and exercise induced asthma combine to mean I am physically incapable of working as hard as I’m motivated to do - I have repeatedly almost put myself in a hospital trying.
However, I have feel and a sense of the horses which many other people don’t, and also an ability to work through fear rather than be crippled by it as some people are. Those are talent advantages. I also am lucky enough to have a job and live in an area where I can afford two horses to be in full training - so when my asthma is bad, I don’t ride but my horses get worked, and when it’s not bothering me, I do.
The one consistent factor is the real top riders HAVE to work hard. I would say someone like George Morris who claims to have had little talent, or Sally Swift who had physical challenges and a brilliance at explaining things, can really make a huge difference, and obviously CAN still do well. But they really shine as instructors for the amount they have had to work.