It's just a phase....Any sufficiently advanced civilization, after a while, will give up on space exploration. Maybe send a few probes here and there, to collect some extra rocks missing from their collection.

There is only so many Neutron Stars, Black Holes, Nebulas, Planets and Comets to study and after you have studying a few million, they all look the same. Once you've seen one supermassive black hole bend light and time, you've seen them all.

You will grow out of it....