To go off what some people said characters who would be considered foundational vs. integral, to me what I see it as certain characters may not be foundational or necessary, but the relationships and interactions are.

It doesn't matter who the supporting cast is, or who the villain is, as long as Peter/Spider-Man has someone to bounce off of, relate to, and interact with. So for example, you don't need JJJ to be in a Spider-Man story, you could easily put any other character to fill that role, but you may be more likely to want to use him because you have a perfectly good character there that already exists, that also has a great history and is very popular and iconic.

And I think that's the big difference, its not exactly who you use but how you use them, and when you have such an expansive castlist like Spider-Man, each with their own distinct personalities and character roles, they feel more necessary because you want to see more of them.