The big difference is that in the Algol 60 family bounds checking was enforced.
"Many years later we asked our customers whether they wished us to provide an option to switch off these checks in the interests of efficiency on production runs. Unanimously, they urged us not to--they already knew how frequently subscript errors occur on production runs where failure to detect them could be disastrous. I note with fear and horror that even in 1980, language designers and users have not learned this lesson. In any respectable branch of engineering, failure to observe such elementary precautions would have long been against the law."
-- C.A.Hoare on his Turing's award speech
C and B designers had another point of view regarding security, or lack of thereof.
The point was that the way VLAs were designed in C99, it was a motorway to stack corruption, leading to dropping it out as optional feature in C11 and C++ not even considering them.
I don't see anything in the wording of C99 around VLAs that requires them to always be allocated on the stack. That implementations did so regardless is, arguably, a defect on their part, and a quality-of-implementation issue.
Well, the whole point of VLAs was supposed to placate the math/numeric crowd somewhat, and they generally expect things to be a little bit higher-level than what's otherwise mandated by the C "zero overhead" philosophy. Since VLAs are opt-in, code that cares more about perf could always skip them and not pay the tax.
But yes, it was probably too naive to expect that to work out.
"Many years later we asked our customers whether they wished us to provide an option to switch off these checks in the interests of efficiency on production runs. Unanimously, they urged us not to--they already knew how frequently subscript errors occur on production runs where failure to detect them could be disastrous. I note with fear and horror that even in 1980, language designers and users have not learned this lesson. In any respectable branch of engineering, failure to observe such elementary precautions would have long been against the law."
-- C.A.Hoare on his Turing's award speech
C and B designers had another point of view regarding security, or lack of thereof.