That's always been my take too. It's inconceivable to me that one little planet has millions of life forms yet there's nothing else anywhere on any of the zillions of planets out there.
Scientists say it's impossible to travel beyond the speed of light but we just don't know. 75 years ago people were saying it was ridiculous to have a handheld device that you could use to talk to somebody on a planet from space (Star Trek), my uncle used to laugh at it. Now that device can speak to somebody live on the other side of the planet by video and also take photos, video and a hundred other things.
150 years ago we couldn't even leave the ground. 250 years ago a lot of the gadgets we have now would have been considered witchcraft. Long before that was thought that you wouldn't be able to breath if you travelled at over 30 mph. If we've advanced this far in a couple of centuries how advanced will civilisations be that have been around for millenia?