You could see another comment I made on this story. :) WebP lossy has poor enough visual quality and poor enough file size gains over JPEG (especially after MozJPEG has really squeezed the most they could out of the 1993 format), that it's wholly unappealing to anyone that would possibly care about lossy formats. Google never really advertised that WebP lossless is a thing, so in the minds of many, WebP is a failed JPEG replacement and PNG stands unopposed (even though that's untrue for a subset of images PNG supports).