[ksec]

>When WebP launched, it was objectively better in most ways compared to both PNG and JPEG,

It was not. Optimised JPEG was on par or sometimes better than WebP.

[solardev]

For a given image, that's possible, but if memory serves, the good enough defaults usually led to the WebP version being smaller across a library of image samples, statistically speaking. But that may not have been true for an individual image.

And either format could be manually optimized even more.