I have never understood how higher ed got into the business of remedial education because it is about high school- level work. I suppose we all know why colleges accept kids who cannot do some high school-level tasks.
If you can not produce a grammatical, coherent, and well-structured essay, or do trig and pre-calc, you are likely not ready for a higher ed curriculum. Sensibly, a North Carolina pilot project is moving remediation to the high schools. At that point, it's not remediation, just more high school.