"this" in JavaScript classes why it's throwing this error?

Question

when it comes to this in javascript classes it suppose to refer to the class instances but at somechildmethod() method it don't it throws an error saying TypeError: Cannot read property 'name' of undefined and I know this error will go away if I use the arrow function but I want to know why please!

class parent {
  constructor(name, score) {
    this.name = name;
    this.score = score;
  }
  someparentmethod() {
    console.log("Hi!");
  }
}
class child extends parent {
  constructor(name, score, thirdprop) {
    super(name, score);
    this.thirdprop = thirdprop;
  }
  somechildmethod() {
    return function () {
      console.log(this.name);
    };
  }
}
const child1 = new child("zahal", 1);
const child2 = child1.somechildmethod();
child2();