Who can write recommendation letters for me?

When browsing their web sites, I noticed that apart from those listed academic requirements by different universities, they all require at least two reference letters from applicants, but they did not officially state that who should write those recommendation letters.

Although I have collected several recommendation letters from my former teachers, I found it was quite hard to reach my former teachers whom I had not contacted for many years.

It almost took me two months from the day I sent out my first email to the day I got enough recommendation letters from my former teachers.

It has been puzzling me why the recommendation letters should be written by school lecturers or professors.

The people who know you best are your close friends, family members like your parents, siblings, why they are not qualified to write the recommendation letters for me?