These kids have spent the time to develop their chops. Quite amazing, I appreciate your sharing.
I feel the time spent daily is the most important factor in developing your skills.
The years come second along with consistency.
In my 20s through to late 40s, typically I would play from 12 to 18 hours a day, basically married to my instrument, obsessed. Learning and playing most of the daylight hours and then playing top 40 rock in clubs 3 to 6 , sometimes 7 nights a week. In those times I could play most anything I heard in my head. Now at 70 yo It's more like taking chances. lol
Thanks for jarring my memory bank, because I remembered many other points, which are way too long to do it justice, and be in this reply. I'll soon write a blog with my personal views.