lot of my mates did not even end up going to uni and resat at sixth form and are now in dead end jobs which is a bit sad.
I would say school has some part to play in how people end up in their current work situation. However from my own personal experience I'd say it comes down to personality and if you have that drive to find something you really want to get into.
I didn't do well at school, I had to do an additional year at college to get something half decent as a qualification. I worked ~360 days straight with 4 different jobs at one point because I needed/wanted the experience.
This isn't a dig at your friends for being in a "dead end job", I feel if people really want to do something that they enjoy, it's not always as difficult as people make out if you're willing to put in the effort.