Weight is relatively irrelevant, as long as people can lift them within health and safety regulations. For shipping in container ships or on trucks, at this order of density magnitude, it's ~free. Re. "Installation and labor" ... many issues here from a western context are likely safety/regulatory driven and not technically driven. In any event, weight reductions are meaningless if you aren't allowed to install it on the roof, or if the first gust of wind breaks it in half because it's acting like a sail. In many cases likely the mounting/frame weighs more than the panel.

Macro-demographically, with more people moving in to apartments globally, the residential roof thing is more a temporary western thing than a utility scale solution to global residential macro energy needs. The Chinese know this better than anyone.

The true economics of industrial processes are rarely clear to consumers.