Suppose I am on a walk in the forest and see an ants nest. I may have a look at it but not tunnel into the passageways to get a closer look, its not my thing plus I have seen them before.

If I find it to be a particularly interesting ants nest I may visit it again the next day and so on.

You will appreciate that for intersteller spacefaring aliens visiting earth to have a look 'next day' for them is about 10,000 years for us.

There is a problem of scale. They live for hundreds of thousands of years and travel interstellar space which is their home. For them we are creatures that exist only briefly on a grubby planet, and not the only ones.

So there are aliens but they are not here.