It’s not automatically bad that they have to retake a class in college that they took in high school. The simple fact of the matter is, unless you took AP or CLEP courses in high school, you have had no exposure to the difficulty of college courses. This is nothing new.
These remedial courses did not exist at state universities when I attended in the mid 70s and early 80s. It was sink or swim and many entering freshmen sank. 30% of the students on my dorm floor did not come back after Christmas my freshman year. These students learned an important truth at a fraction of the cost of underperforming their way through a four year program. So, you are correct that unprepared students are nothing new.
What is new is the erosion of standards for what used to be a college prep high school diploma. This has been accompanied by an increased view of educational egalitarianism- that all should go to college, not just those who through a combination of aptitude and hard work were well prepared.
I don't think this move has been altogether altruistic - look at the explosion in the number of colleges, the market for student loans, and for textbooks. This is big business. Others in the thread have correctly noted is that the colleges are not really footing the bill for these remedial classes - these costs are passed on to the student. Colleges and lenders are quite happy to let a student fund these courses with loans. The 'dirty little secret' is that these courses and costs do not count toward the degree. The student acquires debt for what they should have learned in high school.
This also means that the taxpayers (like us) who typically paid for that high school education have been defrauded as well - the student was given a diploma without possessing/retaining the expected skills.
Excellent point.