The first iteration of JPEG being named simply “JPEG” was a pretty dumb move in hindsight, since their subsequent format naming seems to be e.g.:

• JPEG
• JPEG LS
• JPEG 2000
• JPEG XR
• JPEG XT
• JPEG XS
• JPEG XL

I think it’s a net neutral that the name is JPEG XL when people are used to JPEG. It gives credibility to the format and it’s easy for normies to understand that “oh this is JPEG but better now.” Regarding whether it will “die” due to this, I don’t think that’s likely. People don’t shy away from using PNG or GIF because the names are incomprehensible. They use those formats because that’s what you use for images. If all websites and image programs start defaulting to JXL files, then that’s what people will end up using in short order. Especially since you can losslessly convert JPGs, PNGs, and GIFs to JXL, this conversion could happen literally overnight if needed.