My position isn't that there's "nothing wrong or unfixable about Jpeg" at all. There's lots wrong and fixable with JPEG. My problem with WebP is that it currently doesn't fix enough of the problems that JPEG has and that if we adopt it right now we might end up with another format that still has problems and will have to replace WebP with yet another format that fixes those problems later. JPEG took 6 years to standardize and has lasted for nearly 20, this suggests that we might not want to rush to commit to a 8 month old image format with a bitstream that was frozen the moment it became public.
As for support in other browsers, WebM is supported by Opera, Chrome and Firefox, plus it solves problem of being a royalty-free modern video codec and neither Safari nor IE have obliged in short order. What do you think that WebP brings that will make adoption happen faster than WebM?
I think let's just agree that Jpeg has a lot of problems and we'd like to seek the best replacement. Obviously high-compression rate is important or else everything should migrate to PNG, but the current Jpeg tradeoff between quality and size is not just not very good. Also interestingly, there seems to be a very wide spectrum of Jpeg lib quality from decent to very bad, and I found out about that while experimenting with WebP.
WebP is different from WebM in that there are IP issues. I think WebP is more like SVG/Canvas in that vendors don't see any "hurt" in supporting them once there is enough momentum behind. Of course, your point about making sure that we don't want to support any half-baked image format. I think WebP is beyond half-baked, and an initial pledge of experimental support -- instead of an outright rejection which seems to be tone -- doesn't hurt.
As for support in other browsers, WebM is supported by Opera, Chrome and Firefox, plus it solves problem of being a royalty-free modern video codec and neither Safari nor IE have obliged in short order. What do you think that WebP brings that will make adoption happen faster than WebM?