Sept 9 : The first iPhone in 2007 mainstreamed touch-screen technology, years after it was developed. Now Apple is betting its maiden foldable phone can do the same for a format stuck in a niche despite years of efforts from Samsung and Chinese rivals like Huawei. The foldable iPhone, expected to be unveiled at Apple’s Cupertino headquarters later on Wednesday, marks one of the biggest changes to the flagship device that brings in around half of…