Stan Lee has repeatedly stated that he absolutely didn't expect Spider-Man to last this long. In a number of ways, that's led to precisely the sorts of problems that a number of fans and creators alike have identified with the franchise over the years, but in many other ways, I suspect the reason the franchise has even lasted long enough to BECOME a franchise is precisely BECAUSE Stan wasn't thinking in the long-term when he created this stuff, because if he had been, I suspect it might have been a lot "safer" and a lot less compelling.