It seems to me that as enormous as this universe is, and as old as it is , that there are a lot of possibilities of inhabited planets, and in all aspects of development.
There are actually probably enough inhabitable planets that space travelers might find, that they should not necessarily need or want to come here, destroy us, and take over our planet.
It is possible that this could be the case, but to my mind, equally possible that a higher civilization might come here and help us.
It is also possible that we could use nuclear bombs, and destroy all human life here, all on our own, or that a comet strike might throw us out of orbit, so life is not guaranteed , in any circumstance.
Personally, I would not be surprised if we already had "visitors" from somewhere.
If you look back over history, nothing much really changed in how humans lived for the last few thousand years.
People lived in wood or rock homes, and traveled either on foot, or using horses or other livestock, depending on what part of the world they were from.
There were inventions, but nothing that revolutionized the world, once the wheel was developed.
The rich lived better than the poor, for sure, but even they did not have any real conveniences, compared to how we live today.
Around the start of the 1900s, things really started to change, and in the last 100 years, we have more new developments than we had for the last 2000 years. What happened ? Where did writers like Jules Verne get their advanced ideas ? What about Tesla ? Did Eisenhower really meet with aliens when he was president ?
Something happened that led to huge changes in this world, that is for sure.