I started teaching Mathematics in the US higher education system in 1978, and retired in 2017. Throughout my career, I spent a lot of time reading about the latest trends in Mathematics Education, including participating in several grants.
The basic problem has not changed since Euclid. To understand Science, you must speak its language, which appears to be Mathematics. And it isn't just the hard Sciences. Every study on college success indicates that grades in Mathematics courses are the most robust predictor of graduation.
Despite multiple major revisions of technique and content of teaching, the success levels have not changed since I started teaching. My personal observation is that the overall mastery has declined, as the system now forces students through who would otherwise not succeed. In turn, this grade inflation means that the upper tier of students are often not challenged to work very hard, and so arrive at higher education with an inflated sense of their capacities, and an inability to rectify their deficiencies.
This slight gain through grade inflation, of course, does not satisfy administrators in education, and politicians. They know that the relatively high level of Mathematics failure is because the subject is “too abstract” (ignoring the evidence that this is precisely why it makes people think more precisely), and that Mathematics teachers are universally incompetent.
There have been several efforts of reform in this particular direction, including the English GCSE system, starting in about 1980. The entire curriculum was changed to make it project- and problem-based, using all available technology, starting with extensive calculator use (as opposed to the slide rules and log tables that we had), and moving into computer Algebra systems.
After 20 years, the results came in. Universities reported that students arrived unprepared for coursework that had previously been standard, and even had to emulate US institutions in including remediation. Companies that had hired people with A-levels in the subject reported that they did not have enough skills to learn what was needed for their jobs.
It was a disaster, but as always, no-one would admit that and simply move back to the 'old way' of doing things. Consequently, they had to introduce huge curriculum revisions and claim that they were 'new' ideas.
“The more things change, ...”