Let's be clear though, there's quite a difference in doing problems related to working memory, mental computation, etc. under time constraints - usually what you get when taking standardized tests, aptitude tests, IQ tests, etc. - and solving "actual" real world math problems, like mathematical modelling, numerical methods, and what have you.
I'm sure if I walk around in the office and ask people a problem like "Car A starts driving south at time zero, with speed 30km/h. Car B is located 10 km down south and starts driving north 5 minutes later, at speed 45 km/h, at what time do they meet? You have 1 minute. Go." a bunch of them will start to sweat, and many will likely fail - even though they have graduate STEM degrees.
I did. My comment was to the “Who is going to trust somebody who got a degree in airline engineering who doesn’t know how to think through a problem without a computer telling them the answer?” comment in the article. Even if you suck at math when enrolling college, if you actually manage to get through some math-heavy STEM degree, you've probably learned the math through your studies.
I also did check out the paper, and it does indeed seem like the number of students that are placed into Math 2 (The lowest or second lowest placement if I read it correctly) has 20-fold increased in just 5 years, while most other Math placements have stayed somewhat stable, at least toward the top.
My conclusion is that the students that simply don't have the math knowledge to pursue STEM-degrees, will either not enter them, or finish them, so that might not be a huge problem? They'll purse other majors that don't require math.
My hunch is also that those that are not interested in math, have found shortcuts to get through their math classes the past 5 years (cheating? AI?). But, then again, what are the chances they'll actually end up working with anything math-related after college?
I'm sure if I walk around in the office and ask people a problem like "Car A starts driving south at time zero, with speed 30km/h. Car B is located 10 km down south and starts driving north 5 minutes later, at speed 45 km/h, at what time do they meet? You have 1 minute. Go." a bunch of them will start to sweat, and many will likely fail - even though they have graduate STEM degrees.