You honestly think that has never happened? It's far more likely that they have than they haven't.
We have no evidence of any form of life existing anywhere other than on Earth.
Sentient life is a big step up from the above in terms of likelihood.
Sentient life with technology so far in advance of hours that they can do interstellar (let alone intergalactic) travel is a big step up from the above in terms of likelihood.
Sentient life with such extremely advanced technology and which exists today is a big step up from the above in terms of likelihood.
Sentient life with such extremely advanced technology and which exists today and which is aware of our existence is a big step up from the above in terms of likelihood. Humanity is utterly undetectable from virtually all of the universe and physical exploration would take trillions of years and would only remain up to date if ultra long term probes were kept in place. If, for example, this completely hypothetical society took a look at Earth 4 billion years ago they wouldn't have found much of interest.
I think it's an enormous stretch to casually claim that the entire chain of unlikely events is more likely than not.
If people with extremely advanced technology exist elsewhere and
if they're aware of the existence of humanity, they
might do some close physical observation and if so they
might be detected. Or they might not, since their technology would be so far ahead of hours that they might not need to come close to observe us or their kit might not be detectable to us. For example, maybe they could put a spaceship extremely close to Earth (only billions of miles away, in the solar system but out of sight of Earth) and send numerous tiny probes from it to do the observations. Or maybe they could be light-years away and do whatever observing they want with technology with have no understanding of and no words for. Their technology would have to be extremely advanced to make the travel possible, so we're poorly placed to speculate on its limits.
Maybe they exist. Maybe they exist now. Maybe they know we're here. Maybe they've come to have a look. Maybe they don't care enough to hide their presence and don't care enough to make contact. Maybe. Maybe not. I think that "far more likely than not" is an unsupported conclusion.