I've been programming since I was 8. I've been drawing since I was 29. I will probably never reach the same percentile of drawing ability that I have with programming ability. That's okay for me because I enjoy it anyway, but from the perspective of training people to do their best work, starting younger can lead to higher ability.
Not to even consider the amount of people who get into their trade at such a young age. I'll be honestly surprised if they make up any significant amount of the population, and I'm saying this as someone in that boat.
I pretty firmly believe nearly anyone can learn to contribute in any area given enough time, but there's a lot of time between 0 and 18, and it's prime learning time when brain plasticity is high and responsibilities are low.
Is it really that controversial to say childhood shapes a kid's future?
Even today, 25 years later I feel like I learn things more effectively than when I was a kid. Certain types of skills benefit from experience and networked thought. Time per day/week is a much more limiting factor though.
you start to learn maths in kindergarten. you don't start to program computers there, usually. there are very good reasons not to do that (screen time!), but it will make learning to program easier later in life.
Lawyers and doctors basically need to memorise facts, apply rules and make deductions. Developers need to do that + math, hence why starting early helps you out, exactly like kids who did math or chess early on are better than their peers who started later.