Lots of problems to overcome before we get folding / rolling phones
Screens without glass means screens where scratches are a problem. No thanks, I was glad to leave behind the old days of phones with plastic screens that would magically acquire scratches from being in my pocket despite never putting anything else in the pocket with it. I guess pocket lint contains a little bit of fine silica or something else that scratches plastic.
It was annoying back when there was hardly ever any reason to look at a phone screen, now that we look at phone screens for hours a day there's no way I'd tolerate a screen that's not at least as resistant to scratching as glass.
Everyone likes the idea of folding phones or phones with rollable screens. Reality bites, though - folding phones will need to be square when folded, or be a trifold, to get a decent aspect ratio when unfolded. Phones with rollable screens will need some sort of frame that unrolls with them to keep them perfectly flat, because who wants to look at a display that's wavy or otherwise non-flat.
Between those issues, the aforementioned scratching, weight (for the backing for folding or frame for rolling) bulk since they'll probably be larger when folded/rolled, battery life (more display = more power draw) and likely durability problems with the first gen (at least) after repeated folding/rolling multiple times a day over a year or two I think when released they will get a lot of hype, but won't prove to be very popular. Especially if they cost significantly more than current flagships, which seems likely. The issues will be worked out eventually, but not for years after they first appear.