There is a legitimate concern with space junk hitting useful stuff or even manned spacecraft but I think space is big and the sky won't appear bright soon. Not all satellites are that reflective and they need to reflect the sun, they don't just glow visibly.

At present, I don't believe there are industry standards / codes mandating minimization of reflectivity. My understanding is that SpaceX has engineered for this from their own internal requirements and "goodness of their hearts" (which may be related to avoidance of public pushback). As we anticipate a major scale-up of LEO in the future, it follows that "cost pressures" may (mal)incentivize players to skip this concern.