I think we have a number of problems at a number of scales:
1. Planet density: planet spheres are everywhere, interfering with the proper view of space beyond. Nebula backgrounds also provide interference. (I keep my backgrounds off to enjoy simple starry backgrounds.)
2. I don't think the game properly models star density from galactic center. In real-life galaxies, the core of the galaxy is the bulge, where lots and lots of the galaxy's stars reside, providing extra illumination. As distance from the core increases, star density per cubic parsec should drop off. Plus the center of a galaxy tends to be thicker than the rest of the galaxy, providing even more stars to illuminate the center.
3. StarMade does not yet model nebulas, and there is a lot of nebula gas at the core of most galaxies, which can reflect and refract light, spreading the light source, so that the center looks like one big light. Hopefully, when nebulas are introduced, some real-life effects like this will be modeled also.
4. Distance culling to keep the game running smoothly. A lot of stuff is simply removed from view until you get close enough, to keep the game running smoothly.
Now for some things that alter the way real galaxies are viewed:
Publicly available images of galaxies typically have non-visible wavelengths converted to visible light for effect. This dramatically effects how bright celestial bodies look. They are actually dimmer than you would expect. However, since this is game about SciFi space, not real space, this can be ignored, and those nebulas and galaxies can be as bright as we imagine.
The nebula gas I described above typically interferes with light, so that it not only spreads the light out, but also dims it. Publicly available images are brightened for dramatic effect. Again, this can be ignored in the game for the sake of SciFi space.
Extremely long exposure times can make other galaxies look extraordinarily bright in photos, especially towards the center, even though, in fact, it isn't any brighter than our own galaxy.