>>33718275it's not a matter of it "having been true the whole time" because it's a fact that there's no evolution between cubone/marowak and kangaskhan. All it is that perhaps at some point in the game development/planning they may have been connected.
Same with butterfree and venonat, just because they might have been originally intended to be related doesn't mean it's been true the whole time that venonat evolves into butterfree.