Speaking as a parent, there are times that you know the child is, in fact, quite capable of the task, and they are not, in fact, trying.

Anyone other than a parent or person similarly close and long-term involved in the person's life, however, has no chance to make the evaluation (and I certainly wouldn't dispute that parents can also blind themselves to certain things based on expectations). Government, etc., programs are NOT in that position and cannot run on the "you're not trying" assumption unless they've got a magical "effort detection device".