Car insurance?

Why doesnt some insurance company give 17 year old drivers a chance, my son was quoted £4000.750 he works on a farm and works bloody hard,but the pays not great, i can understand these young drivers without any insurance, they make it impossible for them to get it, we know its wrong , and iam not condoning it , give them a chance it doesaint mean there all mad drivers .
Answer
Have you considered buying him a tractor or a quad?