And unfortunately, not because of the limitations dictated by the laws of physics.
The main reason why we still cannot explore even Mars is that our biological species is still only on the evolutionary path to intelligent beings. All our progress is connected with gradual evolution, as a result of which not only the brain grew, but we also became more peaceful. At the same time, humans could coexist relatively peacefully in increasingly larger groups. And while at the beginning of our evolution, our species couldn't comfortably coexist in groups larger than 30 (similar limitations remained in our closest relatives, the chimps). Nowadays, even relatively primitive production can involve thousands of people interacting. And even despite the trend towards automation, groups of around 100,000 people can interact in complex technological processes. But, unfortunately, our belligerence hasn't gone away. And while 70 years ago it might have seemed that technological progress would make war not only useless but also condemnable, it's now clear that, given sufficient ideological preparation, every new war finds many supporters.
What does space travel have to do with this? It's simple: the technologies required for space exploration require the unification of even larger groups of people within individual nation-states. Space technologies require the unification of all of humanity. This doesn't mean nation-states must necessarily disappear. Just as no one is forcing workers in a single factory to lose their individuality. Everything arises solely from a confluence of personal interests. However, at this stage, mistrust between different states does not allow for sufficient cooperation for such large-scale projects.
There's a common misconception that all our technological progress is tied to military technology. But this is a misconception, technologies appear where resources are directed. And wars in our history have never ceased for long, and therefore resources for military purposes have always been generously allocated. One might argue that many military technologies subsequently find peaceful applications and bring benefits, meaning that wars are still the driving force behind progress. But, besides the fact that people die in wars (which is terrible in itself), most of the allocated resources are wasted. If the resources allocated to military purposes over the last half century had been directed to space exploration, today we would not only explore our solar system and know the answer to the question of the existence of life on other planets and satellites in our system, but also solve many problems (including environmental ones) on our own planet.
Perhaps the solution to the Fermi paradox is precisely the zoo hypothesis. And the species proudly appropriated the name of sapiens are in fact not only infinitely stupid but also infinitely primitive.