HEIC is based on HEVC ( H.265 ), and therefore requires licensing and paying royalty before using it, most likely paid by Microsoft (Windows), Apple or any of your hardware manufacture. It could cost up to ( capped ) $100M per year for hardware manufacture. HEVC Advance Group has made software decoding royalty free. But you still have to paid MPEG Licensing and Velos Media. Because Apple and Microsoft likely has cross patent arrangement to most of the companies within the group, so it wouldn't matter much to them. But for everyone else, HEVC licensing is still a bag of hurt.

AVIF is based on AV1, by Open Media Alliance lead by Google, is royalty free. ( But not patent free, please don't mixed this up ) It is new and the spec has only been released for no more then 6 weeks. Google doesn't want to pay the licensing, especially when the initial licensing terms for HEVC include cost per streaming. All of Youtube video requires VP9 ( the predecessor of AV1 ) for 2K+ resolution, and does not and likely will not ever include HEVC.

Chrome does not support HEVC decoding even if you have hardware decoding. The same for Firefox. That is why the parent said BPG won't ever be included in browser, or Chrome and Firefox. M$ IE 11 / Edge and Safari both support HEVC.

The most common video compression right now is h.264, which has to be licensed but isn't super onerous.

The newer, better version is called h.265 or HEVC. BPG is a way to use HEVC's single-frame encoding to store an image. HEIC is essentially the same thing, but supported by Apple.

HEVC has ugly licensing, causing a lot of companies to come together to make their own license-free video format called AV1. AVIF is the image format based on AV1.

So nobody wants to go near HEVC, and if they did they would support HEIC over BPG. AVIF might get support, if they think it will be used enough to be worth it.