I think one of the biggest stumbling blocks to algebra is the shortage of good math teachers at every level. My oldest daughter struggled with math, especially algebra all through school. She went to college and called me very excited one day about 6 weeks into her first semester- she said “I am not stupid! I got the greatest math teacher and she has taught me more about math than all the teachers I had before her put together!” My daughter went on to excel at every math class she has had since, and is now a math tutor at her nursing school. Many math teachers I have had could do the problems, but could not explain how to others to save their life.
My husband always said I just had bad math teachers and no one taught me how to do math right. I do basic math easily, because I just taught myself new ways to do it and and am not worrying that someone will see my work. So, maybe I’m not as stupid as I am thinking right now.