I do think it depends on the individuals. Not everyone is built to be a parent, and it's good that's recognised. Some people have a "need" to be a parent and are amazing at it and love it. Obviously there are loads all the way through the spectrum in between as well.
It's also a case of the the person will never know if their choice was right as once it's made you can never live the other life. My DM said to me in my 20s "she was sad for me not wanting kids as I would never know what I missed out on"
But I was a definite for not having kids until I wavered at 30 years old, feeling something was missing and thinking it may actually be nice, and I am so glad I did, it is the best thing ever (from a very non paternal person) the joy and love you give and receive is above everything and watching them grow and develop into these wonderful kids you are moulding, it's fabulous.
It's exhausting, stressful and the most responsible role ever. But pays you back ten fold. Turns out my DM was right, it makes me sad to think I may have chosen differently.
But my family member is child free by choice. They does not feel like they is missing out at all. They love their life. They do not want the responsibility of children, they just wouldn't fit into their lifestyle. They work inconsistent hours, has a hobby that takes up a few nights a week and a weekend day, loves being able to drop everything and holiday wherever, whenever, and couldn't think of anything worse than kids. And as the main responsibility would fall to them, due to their partner probably not coping well in that role, it is probably right not to have them, they have loads of love (and money ) to give, but no time, they would resent giving that up.
They look at my "routine" "structured" life as a drag and boring, I look at theirs thinking I would feel unfulfilled. This is beauty of people being individuals, different choices, different things that make them tick.