First, developer education is insufficient to reduce defect rates in this context. Intuition tells us that to avoid introducing a defect, developers need to practice constant vigilance and awareness of subtle secure-coding guidelines. In many cases, this requires reasoning about complex assumptions and preconditions, often in relation to other, conceptually faraway code in a large, complex codebase. When a program contains hundreds or thousands of coding patterns that could harbor a potential defect, it is difficult to get this right every single time. Even experienced developers who thoroughly understand these classes of defects and their technical underpinnings sometimes make a mistake and accidentally introduce a vulnerability.

I think it's a fair and correct assessment.