Something not necessarily considered.
if alien intelligence is out there, Given how difficult interstellar travel is, what would their motivation be to come to Earth? How likely would they be to do it just for fn or for curiosity? If they ARE more advanced, they would probably already know we are here and what our technological level is (less than theirs.). So unless they want our planet or our resources, they wouldn't come. And if they did want those things, they would likely stay.
When resources are scarce, the idea of space exploration "just for the fun of it," seems a bit silly. For our children's children's children's children I guess we need to be prepared to leave the planet before either we pollute it to death or the sun fails (the latter we have plenty of time for, the former is more questionable.)
If it is as hard for them to get to us as it is for us to get to them, what is it we have that they would want? The Kardashians?