1.You have those with and aptitude for the job.
2.Those with the ability to do the job.
3.And those who heard that programing pays good.

From group 1 No matter what they where doing the can learn the job. If they found it was there calling early, the will graduate ready to begin.
From 2. They understand the material well enough to work. Maybe they are no superstar, but usable.
3. I heard the job pays well. They graduated. They are the people you are complaining about.

In Art, Music and Sports you need to show aptitude before they will waste the time to train you. Not engineering. Pass College goto HR.
The Demand exceeds the supply. Not all those with the ability go to school. An some do not go they skip and take the chance.

But I see the complaints, but not the solution. How does HR separate the Wheat from the chaff.