I will add, if I may, that you (as well as anyone in this thread) will know that your parenting style isn't a sure road to the kids mentioned who end up in drugs, in jail, or out of work etc. It still depends on the child's personality.
But beware not so much "horrible kids", but kids who don't understand the norms of behaving in groups or "know their place", the child who believes himself equal to any adult and thus entitled to call the shots. There is an absolute epidemic of entitled tweens and teens who politely, eloquently but firmly & resolutely declare to teachers and other adults, what they will & won't be doing, raised to think their opinion is equal to the King's. How do you think that serves them in their first job?
The parents, unfortunately, have raised the children in a way that treats them as an adult. Here's the thing: children are not adults. By you deciding that he shouldn't have to use the buggy etc because he doesn't want to and should have that "right", you're more realistically pretending he understands the situation in a way he certainly does not.
How do I know all this? My DD1 (mid-20s) has never successfully held down a job. I thought I was kind, but I was permissive. She is outspoken and polite, well-liked, will jump up and defend herself, or anyone. By high school she just decided to stop going and I gave in because I had left it far too late to have any influence; she was already an independent, adult-attitude person who considered her opinion the only one which mattered (without the age and wisdom to understand the consequences!). Her first job lasted two days because she said she was tired and called in sick. Her second job lasted three weeks, she felt they were "disrespectful" when she was always late. Her third, she just decided she didn't enjoy. Nothing awful, she just felt she wasn't "valued enough".
This is textbook child-centred-ness. Not child-centred parenting. I tried to raise a bestie instead of parenting a child. DS1 arrived later into a bigger, extended family where other people's needs mattered, while all of us were doing whatever it took to placate the unruly preschooler. By then, she was big enough to kick, to run off and hide, tear off towards the road if it suited her. And I hadn't the ability, wisdom nor the energy to try to tighten those expectations in a child who'd been raised to think she was the centre of the universe.
DS1 nowadays is very chilled, but also displays some of the same lackadaisical attitude towards things, and at times the consequences of this have really hurt him. But he still actually listens to me, because he had boundaries where his sister did not. It's not cruel to teach a toddler that sometimes they just have to accept things they don't like. It's kind. And we're supposed to be raising them to function in society - not raise them to be independent solo adults on a desert island.