[jacobp100]

JpegXL and AVIF are comparable formats. Google argued you only needed one, and each additional format is a security vulnerability.

[londons_explore]

And more importantly, an additional format is a commitment to maintain support forever, not only for you, but for future people who implement a web browser.

I can completely see why the default answer to "should we add x" should be no unless there is a really good reason.