It's possible, but the universe is really old, so even though we are seeing stuff that happened 10,000 years ago or 50,000 years ago, the universe is around 14 billion years old, so theoretically there should still have been alien life 50,000 years ago somewhere that we can see it. Unless alien life is just extremely, extremely rare. Or stealthy.

The thing is, based upon our best guesses about where humans will be in 10,000 years or 20,000 years (which are obviously just speculation), it only takes one alien civilization to expand throughout the stars. And within the context of the time frame of the universe, it doesn't really take that long to colonize a galaxy. And you'd think that a galactic civilization would have left some observable marks on the galaxy it conquered.

So the fact that it hasn't happened forces us to re-examine our assumptions. Like maybe we're stuck on this stupid rock for good. Or maybe civilizations inevitably collapse prior to becoming interstellar. Maybe class M planets are the only ones that can sustain life, and they are incredibly rare and highly valued and aliens fight wars of extinction over them. Maybe there is some hard to limit to how far technology can develop. Or maybe after a while species' lose their will to power and begin to decay. Or maybe a lot of alien civilizations value homeostasis over expansion. Or maybe it is possible to expand throughout the stars, but it takes a really, really, really long time. Or maybe alien life is extremely rare. There were a few civilizations in our galaxy, but they died out for whatever reason, are we are essentially alone at least for our galaxy our even maybe our local group.

who knows.