In France many divorces are uncontested, but you're still require to use a lawyer (the same for both spouses).

On the other hand most couples with kids are not married, so the separation doesn't require a lawyer...

Divorce is expensive because it is big bucks for the lawyers and family court cartel. They have a vested interest in not changing the laws. When laws are made fair, and the perverse incentives to divorce are lessened, divorce rates plunge. However, divorce lawyers lobby against these laws.

Kentucky became the first state to pass a law making equally shared custody the default arrangement in divorces and separations.

https://www.wsj.com/us-news/law/the-equal-custody-experiment...: Divorce Plunged in Kentucky. Equal Custody for Fathers Is a Big Reason Why.