I think it's because they're running out of ideas too BUT the current generations of foldables (galaxy fold 7 for example) are essentially indistinguishable from non folding phones when closed. Yes, that means they could have made a thinner phone over all - the Galaxy Fold is the same thickness as the iPhone 17 pro max but both are twice as thick as the air - but I think consumers have gotten use to thick heavy phones - its why the SE and air don't sell as well IMO