Why do you assume that the benefits would outweigh said costs? That's a weird burden to set on the format. Using JavaScript on the browser to decode it is a huge hurdle, I don't know of any format that ever got popular or got its initial usage from a similar approach. Avif was just added too, even if no one was using a js library to decode it beforehand
Fwiw I agree that there's a weird narrative around jpegxl, at the end of the day it's just a format, and I think it's not very good for lower quality images as proven by the linked article in the OP. Avif looks better in that regard.
I think it would've made more sense than WebP though (which also doesn't look good at all when not lossless), but that was like a decade ago and that ship has sailed. So avif fills a niche that WebP sucks at, while jpegxl doesn't really do that. That alone is reason enough to not bother with including it.
People don't use blurry low quality images in the web. These low qualities don't matter outside of compression research.
Average/median quality of images is between 85 to 90 depending how you calculate it.
There, users' waiting time is worth during image formats life time for about 3 trillion USD. If we can reduce 20 % of it we create wealth of 600 billion USD distributed to the users. More savings come from data transfer costs.
> Why do you assume that the benefits would outweigh said costs? That's a weird burden to set on the format.
I'm not assuming that there are those benefits, but that there are people to see them. Those who _very_ vocal about browsers (and Chrome in particular) not supporting it seem to think so or they wouldn't bother.
If I propose integrating good old Targa file support into Chrome, I'd also be asked about a cost/benefit analysis. And by building and using a polyfill to add that support, I show that I'm serious about Targa files, which gives credence to my cost/benefit analysis and also lets people play around with the Targa format, hopefully making it self-evident that the format is good, and from there that these benefits based on native support would be even better.
For JXL I see people talking the talk but, by and large, not walking the walk.
I see what you mean. Yeah, I think jpegxl is the format that I've heard about the most but never really seen in the wild. It's a chicken and egg problem but still, it's basically not used at all compared to the Mindshare it seems to have in these discussions
Fwiw I agree that there's a weird narrative around jpegxl, at the end of the day it's just a format, and I think it's not very good for lower quality images as proven by the linked article in the OP. Avif looks better in that regard.
I think it would've made more sense than WebP though (which also doesn't look good at all when not lossless), but that was like a decade ago and that ship has sailed. So avif fills a niche that WebP sucks at, while jpegxl doesn't really do that. That alone is reason enough to not bother with including it.