I kind of doubt it. JPEG is good enough, and is pervasive. JPEG XL is better, but removing an incumbent file format requires more than just being better. We'll see.
I wouldn't be too surprised if every big CDN already does something like that internally as a competitive advantage, and if so then the incentives switch around and there's no benefit publically switching to JPEG XL - when everyone has it, there's no easy way to do better than everyone else.
A great blog post on this by one of the creators of the format, Jon Sneyers:
https://cloudinary.com/blog/time_for_next_gen_codecs_to_deth...