I think most people writing nonsense like you simply do not grasp the way other people think.
My EX GF in Thailand, is a sibling of 14 kids. Three died in childhood. She is the youngest. If Ginness book would have been around her birth time, her mother would be noted. She gave birth at age 66 or so. My EX is ten years younger than her youngest brother. Six siblings died in young adulthood, and now 4 are left.
(Mostly) EVERYONE in that family has only ONE child. Some have two, because they divorced and remarried and got a second.
No sane person wants more than one or two kids. It is a complete no brainer for a Thai that, 3 is maximum and 1 is optimum.
I have NO CHILDREN, because my childhood was absolutely ABUSE miserable. And I was afraid I make my kids miserable, too. Because: ABUSE is TRANSMITTED!
Modern Thai in general do not have more than one kid. And that has nothing to do with "cost" but how we call it today: life work balance.
If I have a 8 year old kid, traveling the world is easy. If a second one pops up, I am blocked 6 years to have my own life. Most people do not pick that option.
In most countries pre natal care: is cost free!