WebP produced good file size reductions because they recompressed JPEGs and ignored the loss in detail. I benchmarked it the day it launched and it was never once competitive enough to be worth the cost of using it. If browsers had supported JPEG-2000 in the 2000s, it’d have stomped WebP on every benchmark – even a tuned JPEG encoder did surprisingly well given the age of that format.

HEIC, AVIF, JXL, etc. are worth the trouble.