It's the formats you use inside of HEIF (such as H.264 and especially H.265) that can require royalty-payments, although HEIF can also contain JPEG.
Apple will probably just add AV1 support to HEIF. Apple joined the Alliance for Open Media and maybe AV1 based images will be their first AV1 application.
Royalty free isn't good enough, it needs to be a FOSS compatible license or too many free (as in libre) OS's and applications won't be able to support it. Further to that point, the code itself needs to be free in order for users to have guarantees they own the ability, for all time, to decode files. If they don't have decode guarantees, then images can in effect become locked; either legally or practically. And that's not something the world should tolerate.
https://github.com/nokiatech/heif
It's the formats you use inside of HEIF (such as H.264 and especially H.265) that can require royalty-payments, although HEIF can also contain JPEG.
Apple will probably just add AV1 support to HEIF. Apple joined the Alliance for Open Media and maybe AV1 based images will be their first AV1 application.