Please, don't tell me it's talent. That's not the only factor. Might be his training. I can't do anything right now about my training. Practice, practice, practice? I practice as I can, until either my fingers or brain or heart gets tired.
There are a lot of factors and some are so subtle and circumstantial which is completely impossible to know the answer. Whatever little choice, little action and little circumstance you deal with everyday shape uniquelly your life and your skills.
I actually think that one of the factors compromising you is pushing so much effort in learning. When your fingers, your brain and your heart get tired you learn nothing, just stress yourself and your planing apparatus. We all have a limit, a limit of data to memorize or information to understand of physical patterns to automatize. If you're always exceeding those limits you're not only preventing the learning of new things but unlearning the old things as well.
I have already explained that most of piano skills is a matter of attitude.
Some people consciously cultivate such attitude while other people have already developed those attitudes in their life. Patience, confidence, control, coordination, musical sensitivity, joyfull exploration, awareness, calm, pose. It's likely that young guy have most of these attributes developed; either because of has been aware of them or either because of its general living environment and a lot of other factors.
Let me use "weight loss" as an analogy:
1) It's useless to wonder why you neighbour can eat more and lose weight while you don't. The reason for his/her weight loss in spite of more consumed food aremany. You should only care about your weight loss!
2) If you decrease your calories so has to burn more calories than you get from food you lose weight. But there's a limit to that. If you lower your calories so much that your bod detects starvation, your metabolic caloric consumption will lower and you'll get adapted to use fat less energy just to survive and this will hinder your weight loss.
3) Weight loss too needs pose, calm, confidence, control. If you just get obsessed with food and eat only unpalatable disgusting fibrous food in order to eat like a rabbit you'll soon get cravings and go in a binge. All the stress, anticipation, negative attitude won't help your weight loss. You'll lose far less weight than the person who eats in a relaxed manner, try to maintain a caloric control but keeps eating delicious food and enjoying life.
4) The people who are called "gifted" are not gifted with a body that doesn't gain weight. They're gifted with a instinctive signal for caloric balance. In other words they know instinctively when they are in a caloric balance, deficit of excess. So they can eat everything because they know when to stop. Such instinct is formed in the early years of life and completely destroyed by parents who force their children to empty the plate or eat even when they're not hungry and would rather leave the table and go to play.
Sometimes I feel guilty that maybe I'm too lazy, lack perseverance and all... Is that it?
No, it's probably the opposite.
I will keep using the weight loss analogy.
The key is eating less of healthy foods.
You're probably eating too much of unhealthy food.
The idea that more is always better is a nonsense.
Today they published a study from West Virginia university that proved that working that studying too much decreases exponentially productivity. Studying less and working less decrease the producitivity per hour and decrease hugely mistakes and flaws.
It's not that I want to play fast, virtuosic pieces, concertos, or even the most popular pieces. I don't want to be a concert artist
I think the point is that to being a talented players of virtuosic pieces and concertos you need the amount of dedication and hard work typical of someone who is planning to become a concertist. That's why I have never met a total amateur whose only goal is to entertain friends with the family piano being able to play those pieces.