exactly .... which kind of makes those proc pointers not as useful because you need to carefully manage lifetimes/etc yourself and failures are, well, not defined
(define (make-counter)
(let ((n 0)) (lambda () (set! n (+ n 1)) n)))
func makeCounter() (func () int)) {
n := 0
return func () int { n++; return n }
}
IIRC some algol-68 compiler did remove the restriction and allowed such full closures.
Algol60 and 68 were created at a time when people were still trying to figure out how computer languages ought to work (in a sense we still are) and it's likely the idea that procedure local storage should (or could) out live the procedure being called wasn't an obvious choice (remember that algol68 Nests are not just locals of a particular subroutine but also locals of every subroutine in its declaration [not calling] path as well as globals at level 0)
Algol68 (and Algol60) gave us lots of things we take for granted today but there are also features that have fallen out of fashion
(I'm old enough to have seen language features like objects and functional programming come and go, several times ... it's all fashion .... and I'm cynical enough to know that there's no correct way to do any of this stuff)