Doesn't this mean that on a long enough time frame, an observer anywhere in the universe won't be able to see anything because everything else in the universe is too far away to be visible?
Simply - yes. Furthermore, civilizations that arise in that era of the universe will likely have a different cosmology than what we are able to understand today. If you could only see the galaxy that you are in, you wouldn't be able to see galaxies that were forming shortly after the Big Bang, or be able to use supernovas in other galaxies to measure the scale of the universe.
Kurzgesagt did a video on that - TRUE Limits Of Humanity – The Final Border We Will Never Cross https://youtu.be/uzkD5SeuwzM
Kurzgesagt did a video on that - TRUE Limits Of Humanity – The Final Border We Will Never Cross https://youtu.be/uzkD5SeuwzM