I worked in the plastic optics industry for 5 years, injection molding and some casting. Plastic optics for lenses works
fine if small. If larger than 25mm the process is complex plus the limited materials is an issue. PolyCab is the best all around.
It does not take in water like acrylic does. Make many aspheric lenses for imaging systems and make the first optical mouse
optics for Apple, MicroSoft and LogicTech. They used the same design. I don't see much improvement in the coming years
were it will become equal to telescope grade. As far as mirrors, no. We tried to make 1/4 wave plano optics, 10mm, but no luck
Most the mirrors make for bar code readers are 2-5 fringes, were most of the plano mirrors are manufactured for.
So to answer your question, no not there yet and not much reason to. Flat optics is make a large enough scale now using
glass. Polishing plastic is not worth the effort.