My observation would be that many of my “struggling” students do so because they are woefully unprepared. I have had students who appeared to be functionally illiterate, students with the math skills of 1st graders, students who could barely write a sentence. I can’t fix those things. Many of them come from places where not only are there not parents pushing them, but there are barely parents at all.
Another common issue is the level of “expectation” in the student. Many students come into a course expecting the instructor to feed them everything they need, with no effort on their part aside from lounging back in class and watching the professor make it look easy. When they can’t do it themselves (because not so easy), they blame the faculty rather than their own attitudes.