It's never available on homebrew the same day so we all worked hard to make it available the same day on Neon. If you want to try out the JSON_TABLE and MERGE RETURNING features you can spin up a free instance quickly.
maybe you're seeing otherwise but i updated a min ago and 17 isn't there yet. even searching for 'postgres' on homebrew doesn't reveal any options for 17. i don't know where you've found those but it doesn't seem easily available.
and i'm not suggesting you use a cloud service as an alternative to homebrew or local development. neon is pure postgres, the local service is the same as whats in the cloud. but right now there isn't an easy local version and i wanted everyone else to be able to try it quickly.
https://neon.tech/blog/postgres-17
(note that not all extensions are available yet, that takes some time still)