Wise Exploration

While self-replicating spacecraft would have a potential to bring life and technology to a whole galaxy in a matter of just a few million years, it may not be the wisest thing to do. The exponentially replicating probes would potentially create competition, accelerate resource consumption, and take away the chance for other types of life to emerge, preventing the possibilities to study other types of life, which might provide insights into overlooked optima to reduce our own biases, the knowledge of which may be useful for future road- blocks. All of that combined, releasing von Neumann probes would have to be treated with the same caution and foresight as messaging to extraterrestrial intelligence. (Advanced alien civilizations may already exist, and be monitoring the universe for emergence of replicators.)

All that brings me to an assumption, that any sufficiently advanced civilization is secure, wise, curious and patient enough to be uninterested in polluting the universe with von Neumann probes, because they had assured their survival with sufficiently high certainty (e.g., diversifying with just a dozen of mutually remote independent civilizations makes probability of extinction vanish), that making exponentially replicating probes does not enhance their chances in survival (but instead, reduces it by accelerating resource consumption, and creating other risks mentioned above).

In that context, leaving the resources for other types of life to emerge may seem more interesting and deemed useful.

As a side effect, in that case, one would not expect to see the universe teaming with life (like Fermi paradox supposes), but instead, a universe with different types of advanced civilization clusters, with hidden locations, and encrypted signals to each other about their existence and developments, where each cluster is not unlikely to be aware of another. Whatever dangers they would encounter, would likely not divulge the locations of other civilizations, but be able to inform them.

In other words, wise exploration instead of pure replication.

One does wonder, however, what would happen if such advanced civilizations do get in contact despite taking this wise exploration strategy.

NOTE: We do need to run some simulations for this strategy, but if this proves to be a better strategy, then it weakens the predictions of Ray Kurzweil, that we're just one civilization, and the predictions of Nick Bostrom about the "great filter," that prevents civilizations to further develop.