The main problem with new file formats is adoption. JPEGs have been the main image type online ever since the world realized that GIF sucked. Boards that allow image posting allow JPEG, social networks etc. which allow profile pictures allow JPEG, image search engines catalogue primarily JPEGs, almost every site's design utilises JPEGs. Offline it's the same; every OS which allows background images uses JPEG. Every image viewer and editor works with JPEGs. JPEGs have been an integral part of the internet for so long that I heavily doubt that any new format, superior or otherwise, will supersede them for a long time.