A civilization that can colonize the galaxy WILL colonize the galaxy. How long is 10,000 years if a society discovered warp travel 1 million years ago, or 100 million years ago. The universe is around 14 billion years old. If someone had a warp drive a billion years ago, they could have crossed the galaxy 100,000 times by now.
We colonize the earth but we haven't colonized the ocean trenches.
We have nukes, but it doesn't mean we set one off every day since we invented it.