Why are distant galaxies and stars so hard to see?

because they are so small, they must be magnified
because they are so large, their images must be reduced
because the light is so spread out by the time it reaches your eyes
because they are so bright, the amount of light must be reduced

because the light is absorbed, scattered or distorted by objects and dust particles in the interstellar space, making it difficult to detect them. Additionally, the vast distances involved mean that the light from these objects has to travel for millions or billions of years before reaching Earth, which makes it weaker and harder to observe.