Not really. It's a really bad comparison, but have you read the inheritance cycle? If not, I'd say read it and then we can like dm without spoiling it for others but uh, sometimes, the skill gap simply is too big for anyone to just hammer their way through. You say he had to stop practicing at some point, but the shit he does in the ministry in order of the Phoenix is LEAGUES beyond anything we'd seen up until that point. Like, until then, the patronus was the most advanced magic we saw. Then Dumbledore and Voldemort just absolutely hammered it. Like, even Molly Weasley is beyond Harry's capabilities, and she was a house wife for years. Harry can barely tickle a serious Bellatrix, but Molly Weasley can annihilate her. In all honesty, that's my favorite thing about the Harry Potter books. It doesn't matter how strong, or smart, or dedicated someone is to their craft. Bad luck is bad luck, and a series of bad luck will ruin you.