The Bourbaki group was reponsible for the Mathématiques modernes movement which intended to reform basic education on rigorous math. This may be the world's best documented educational failure in history. It was tried in several countries, so the sample size isn't one. All evidence points at rigor as a terrible educational tool.
The point of Math education isn't to create a clone army of the most pedantic pure Mathematicians in Academia.
> if you really think it's so effective when many demonstrate a lack of understanding all around us. That so many struggle with calculus is evidence itself
New Maths often called a failure but there's not real clear evidence that's the case. This is especially true in America where criticism was quite high as parents were quite vocal and struggled to help their kids (remind you of a different movement?).
There is a certain irony with that too. The major criticisms were about the de-emphasis of arithmetic, arguing that this is the skill people need more. Here we are today though, where everyone has a calculator in their pocket. Plus, people still struggle with extremely basic arithmetic such as calculating a 10% tip... SAT scores are commonly pointed to as evidence, but in the same period of time Verbal skills fell even more[0]! Would you suggest that New Maths was so bad that it made people worse at English? Or maybe there's another explanation like how the number of SAT takers dramatically increased, especially from those in the bottom percentile of high school[1,2].
If you explore the NAEP data[2] there's no decline and there's been progress the entire time for math scores for ages 9, 13, and 17 (the ages that participated).
The Russians famously did very well too.
It would be even a greater irony if we concluded something was a failure because we made mathematical errors in analyzing...
The point of Math education isn't to create a clone army of the most pedantic pure Mathematicians in Academia.
> if you really think it's so effective when many demonstrate a lack of understanding all around us. That so many struggle with calculus is evidence itself
Because the first attempt went so well.