It’s still bad compared to modern lossless algorithms. PNG is very old and even though PNG encoders have evolved, it is still fundamentally a decade behind modern lossless compression algorithms.
For example: JPEG XL in lossless mode compresses at least 30% better than PNG.
Also, PNG is not actually lossless in many cases. PNG only supports RGB colorspaces. If you try to store anything that’s not in an RGB colorspace (e.g. a frame of a video) in a PNG, you will lose some color information as colorspace conversion is not lossless. Example of someone running into this issue: stackoverflow.com/q/35399677
JPEG XL supports non-RGB colorspaces so you don’t have this problem.