Since I wrote that post I've learned a little more about other solutions being experimented with elsewhere, and I think offering remedial support is important but I have a clearer picture of the problems with traditional remedial course progressions and where the attrition actually happens (it turns out it's in between the remedial courses, not in the courses themselves). I think there are some ways forward that somewhat solve that attrition issue without lowering the bar.
And I agree that the correct fix to bad primary and secondary school learning outcomes has to be focused on the school and home environments of students in primary and secondary school. I also think the current structure of higher education (a service you buy, at great cost, typically with non-dischargeable debt) makes detours (like remedial course sequences or just failing to place into a course for a given semester) and failed experiments (getting admitted to a school or program you're just not ready for) extremely costly and high-stakes for students.
Issues crop up here in university classrooms and university admissions offices, but it's obvious that the problem's root is nowhere near there.
I kinda wanna contest one thing, though: the function of college degrees in the job market is a credential that signals, among other things, a competence floor. "Keeping" people (virtually always adults, by the time the enter university) longer should be minimized where it doesn't produce more competence (something that cannot be measured by completion rates). But if efforts to shorten that path achieve that goal by diluting the accuracy of the credential as a competency signal, downstream consumers of that signal will just stop relying on it. That's what is happening here with universities bringing back the use of the SAT in the face of the competency signaling failure of high school diplomas, and it can also happen with community college transfer credits, associate's degrees, or bachelor's degrees. And when the problem hits the job market, employers are likely to turn even more to that diffuse set of signals (personal networks, clubs, vibes that draw on stereotypes, legacy networks, credentials that take even more schooling) that are actually worse in equity terms because they are more informal, more path-dependent, and harder to crack for skilled and talented people of disadvantaged backgrounds.
It's true that sometimes employers or universities or others are looking for largely arbitrary filters, because they have more qualified candidates available than they actually can deal with, in which case the function of a college degree or a high school may no longer be primarily about signaling a competency floor. I think that case is even worse, though. Consider the case of universities: instead of buying test prep or subject area tutoring, high SES families end up seeking to reproduce their advantage through favors, legacy networks, interview coaching, application coaching, etc.
Degrading the competency signals of educational credentials creates a cascading fraudulent promotion failure. Degrading or eliminating the aptitude signals of quantitative entrance tests ends up burdening the people who are supposed to be helped with not just failure and detours but massive debt. You can't solve scarcity problems by removing information.
Thanks for your engagement and sorry for writing too much. :)