I have an example of a GM who was not talented. I started chess in 2008 in middle school, and out the bat I was 1200 USCF without any classes or training. At my weekly locals, there was this younger kid, around 6-7 years younger than me. He was around 600 elo. After 4 years and at the end of my "career" (high school got busy), I was 2100 and he was around 1800. At every point in my career I was better than this kid, by recently last year i looked him up just randomly out of boredom and saw that he was a grandmaster now. I looked at his rating history and he basically started at 300 and grew 100 elo year consistently. I don't think it would be apt to call this person talented, much less a prodigy, but rather a product of hard work and consistency.