h265 is doomed because of the multiple patent pools that have formed and the extreme price hikes compared to h264. It's a risky technology to build on. That's the best ad that AV1 can have, and many members joined the alliance for open media for that reason after it became clear that the patent pool situation wouldn't resolve.
As for your browser support question, yes, Safari has traditionally been anti-ogg, but a few years ago Apple joined the alliance for open media and added opus support to their browsers (although only in the caf container, for some weird unexplainable reason).
Open codecs have won in the lossless audio domain (flac). There is no reason they can't win in the lossy video and lossy audio domains too (not sure about lossless videos but FFV1 seems to have lots of support by archivists who want open technology).