If you're surprised by this, then your mental model of the world isn't correct. Might be time to re-calibrate your expectations if you (like I admittedly did) went to school in a nice neighborhood where 90%+ get a 5 in calc AB.
This is snobbish at best. Apart from the fact that there are various social and economic barriers it also isn't easy for everyone.
Perhaps you are biased from being surrounded by developers but It's akin to me (a non farmer) making a blanket statement like "Surely it isn't so hard to grow a tomato. Why are all these people in Africa starving?"