No matter how much LL and the FS team fixes viewers and makes PBR available to more people, there will still be many who simply can't use PBR. Their current option is to use the older Firestorm release, which the FS team has promised to retain online indefinitely. But in such case PBR items (becoming increasingly common) appear solid white. That is not a desired experience.
I am wondering if it would be possible for LL to create a "PBR Translator" for systems that cannot handle PBR / Advanced Lighting. Such a Translator would convert PBR textures to a suitable Blinn-Phong approximation, so that PBR items don't appear solid white.
Such a translator would make the system more usable for a lot of people, and perhaps less laggy and crash-prone than the current system.
I learned a long time ago that when it comes to computer software, practically nothing is impossible. It all depends on how dedicated someone is to achieving that goal. One would think for the sake of Second Life overall and the users who have been using it for years (as well as new ones who may be trying SL for the first time)... that a PBR to Legacy graphics translator would be a sensible addition.