Viewing some planets optically like Jupiter, Saturn and Venus don’t really require dark skies. Light pollution has little effect on them unless it’s extreme or you’re real close to street lights etc. Stars and deep space objects are much dimmer and do suffer immensely under light polluted skies. Those with larger scopes sometimes use filters in their optical train to filter out some of the harmful light wavelengths such as emitted by mercury vapor lights.
It is amazing how much brighter the stars are way out in the undeveloped countryside.
I recently read a magazine article that said the new LED streetlights are going to reduce light pollution a lot. LA is going in for them in a big way.