Spider-Man's villain roster is way bigger and more powerful than Batman's, Batman's villains often give him some kind of detective plot to keep the story up. The entire Spider-Man villain roster would completely roll over Batman.
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I am in your algorithm learning all your mannerisms
I'm already level with God
A million words a second and I know your imperfections, baby
I'm the only future you've got
Speak in diatonics, motivation diabolic
I'm like a religion, better locked in a box
Picture perfect image, more powerful every minute, baby
I am everything that you're not
Spider-man most often outsmarts his opponents. Batman could do the same too but it requires more prep time. Most of Batman's rogues are highly intelligent such as Joker, Harley, Riddler, Penguin, Scarecrow Two-Face so Spider-man can easily one-shot them. Spider-man's Rogues on the other hand (Green Goblin, Lizard, Venom, Doc Oct, Kraven, Scorpion) have superhuman strength and durability that will give Batman a hard time to overcome especially if they are fighting to the death. Moreover, Batman is a normal human. Spider-man can at least take a few punches. So Batman will die first.