(Heartfelt thanks to 'Irisviel Emiya' for the 2476 reward, and to 'Desire to Fly Without Heart,' 'Lei Xiang,' 'Yunqi Qinggu,' and 'Che Ming Kuang Shao' for their rewards!)
Indeed, shrine maidens who served gods should all be able to hear the voices of the gods they served.
Not to mention that on Youkai Mountain, there was a Moriya Shrine. The shrine maidens there could not only hear the voices of the gods they served, but even lived with those gods every day.
However, the shrine maiden of Hakurei Shrine, Reimu—or rather, the Hakurei Shrine Maidens before Reimu—had all been unable to hear the Dragon God's voice. At least, Wu Yan had never heard of it in his memories.
At first, Wu Yan had thought it was because the Dragon God was special. After all, the Dragon God did not actually exist within Gensokyo and had gone somewhere unknown.
But now, judging from what Purple said, Hakurei Shrine Maidens had apparently been able to hear the Dragon God's voice in the past, only to suddenly lose that ability at some unknown point in time.
Combined with the fact that the Great Hakurei Barrier, which should not naturally weaken as long as the Dragon God existed, was being weakened, and that Reimu, who should have been able to sense the Barrier's condition, had yet to notice any changes to it, everything made Purple begin to wonder whether the Dragon God no longer existed.
No matter what, the Hakurei Shrine Maidens had once borrowed the Dragon God's power to establish the Great Hakurei Barrier. Since they could sense the Barrier's condition in the past, they should still be able to do so now. There were only two explanations for why they could not.
Either the connection between the Hakurei Shrine Maidens and the