what if they've been in space for so long their bodies can no longer handle being on a planet with gravity?
what if all the tech we have is from them slowly teaching us how to use their tech to communicate with us?
what if we're just in the phase where we're figuring out our differences as an intelligent species just before we make final contact with them?
what if our warlike nature is the only reason they aren't openly communicating with us?
what if they eagerly waiting to show us the answer but we need to reach a certain level of enlightenment first and are well on our way?