The problem is, though, that students are being graduated and then admitted into colleges without being able to write. Unless the student is enrolled in a remedial program of some sort, it should not be the responsibility of the COLLEGE professor to teach basic writing skills.
The college is admitting them without them being able to write. They know this is a problem. So, they either need to accept that the college professors are now de facto high school teachers or they need to not accept the students in the first place.
I agree that is a big part of the problem. Too many (non-elite?) colleges are run more like businesses these days and seem to only care about getting the admission monies, whether the student is prepared or not.
I think part of the problem is also the incessant calls for everyone to go to college, when it is quite clear that some people should not- even some very bright people are not meant for college. The US could really use a good technical and vocational model for those kids.