Because it would be harder to do that design/color in the rubbery material used for Widow and Batman's boots, I reckon. You can clearly tell that those other figures had bendy, rubber boots in the pics. Spidey's pics make him look like they are hard plastic and, as previously mentioned, they don't bend at all in any of the promo pics even when it looks kind of silly because of it.
Maybe they will make changes, and I could be wrong, but the available evidence suggests that the boots ain't gonna allow for much ankle articulation.
Maybe they will make changes, and I could be wrong, but the available evidence suggests that the boots ain't gonna allow for much ankle articulation.