Obviously there's no way to tell what's going to happen long term, but all the material used in side body cladding has improved over time. I can certainly sympathize with the horrible material used in the bumper covers Subaru has sold for many years. Overall, the only way to keep any black/unpainted plastic looking nice is to ensure it has a protective coating (whether chemical or physical), and of course there is no shortage of companies willing to sell you on their product.
So far, for all my bumper covers over the years, the longest lasting product that reduced the white haze is the original Turtlewax ICE liquid wax. Unfortunately, they have about 100 different products now with practically the same name so I can't say much about whether any of those work on black plastic (but that's the key thing to look for). I did grab one of their ceramic products after seeing it put through the paces on the YouTube Project Farm channel and it has worked fantastic on the paint though not as noticeably well on the black plastic as the ICE wax.