The original media broadcast here is just another part of the agenda for a fake invasion, it wasn't a real psychic prediction, merely an attempt to put the idea in the masses brains in order that the parasites had permission to activate that plan.Why do we assume they are invading? What if they enter our space, then introduce themselves and ask to land?
But to answer your other question, ets have been here for a long damn time but they don't have permission to land here anymore than the parasite controllers do. It requires a mass subconscious contractual agreement to do so.
They have been asking to land for many years, many species have, and some have been given permission to do so in the past but under technical red tape bs concerning the planet, permission slips and what not, there was a lot of false pretenses and violations of universal laws by doing so.
So basically, they have already asked the minds and higher selves of all of the people here, in the heads of the people here they need permission from a certain percentage of people before they can. It all comes down to the non interference thing, they can get away with certain things like showing their ships to get caught on camera but they are by the book idiots in my opinion, when the trials come they want to be able to say they acted in good conscience.