The simple truth is that JPEG is more than good enough and has ubiquitous support. There is no reason to switch to a different format and risk degradation or reduced interoperability for slightly smaller file sizes.
I don't understand fanatically chasing smaller image sizes when JPEG was good enough for the web of the 90's. There must be a different reason to throw some of the highest paid engineers in the world at WebP and it ain't generosity.
Google spent a large amount of money purchasing On2. WebP and WebM were a way to show shareholders that they were seeing benefits from the acquisition, and if you look at Google’s traffic volume you could make an argument that even a modest size reduction would pay for the engineering time.
The problem was that this was basically only true for the largest sites. If you’re YouTube or Netflix, it pays to optimize your video encoding but for most other sites the volume just isn’t there and the performance costs for anyone who uses a CDN cancel it out because you need a lot of traffic for each format before a 10-20% byte size reduction saves more time than the cache misses take.
