The universe was indeed vast and empty. After reaching Level 4 Civilization, Human Civilization felt this more deeply than ever.
Even with such advanced interstellar travel capabilities, they had traveled hundreds of light-years without finding a single life planet, let alone encountering another alien civilization.
At times, humanity even suspected that all those alien civilizations they had encountered before had been deliberately arranged by Awakener 'Illusion'. Now, however, they believed Awakener 'Illusion' was still occupied with the war against the Harvesters and had no time to watch over Human Civilization, which was why they no longer encountered alien civilizations as frequently as if everything had been arranged for them.
Humanity was right that Awakener 'Illusion' was no longer watching them, but they were wrong about the war between the Awakeners and the Harvesters.
With no relevant information, it was only natural for them to guess wrong. Of course, humanity did not know that yet. They still believed the war would last tens of thousands of years.
Humanity was still on the Starry Road, generally heading toward the end of the Orion Arm, though they had no precise destination. During this time, they had not given up observing the vast Galaxy. They still clung to that sliver of hope.
During Warp Speed Travel, the faster-than-light velocity made it difficult to observe the Galaxy's stars through the light in space. Thus, whenever they stopped to resupply, the astronomers impatiently deployed the Sky Survey Telescope Array and began observing the stars.
They had two purposes. First, they needed to determine their position in the Milky Way Galaxy. This was crucial; the slightest carelessness while traveling through the stars could leave them lost in the boundless sea of stars, so every stop involved locating themselves and correcting their route. Second, they observed the position