I'd agree that it is important for children to have both responsibilty and trust at a young age. It is scary to have them around sharp stuff, and it's a lot of work, and requires lots of vigilance, too. Nevertheless, things have worked out well for my kids and grand-kids - and hopefully soon, my great grand-daughter.
The problem these days is that parents often want to avoid what they perceive as unnecessary danger with younger kids. In my opinion, they are really avoiding the work and vigilance needed. And so we have teenagers who have never learned about danger or responsibility taking control of a car. Often that's the first dangerous metal object they've had control over - and so things can go very badly.
Things don't always go well in life, and if a parent wants to be able to talk to their kids who have become adults, then they sure better have put in the gruelling parent work in the past. Now I do look back and see immense amounts of fun and good times, but it was a job which I luckily took very seriously.
No Mannertags here, though, too many grand-daughters...