Unlike Docker Inc, GitHub (via Microsoft) do have very deep pockets & their own entire cloud platform, so they can afford to do this forever if they choose.

And their entire marketing strategy is built around free hosting for public data, so it'd take a major shift for this to disappear. Not to say it's impossible, but it seems like the best bet of the options available.

Is it practical to set up a redirect in front of a Docker registry? To make your images available at example.com/docker-images/abc, but just serve an HTTP redirect that sends clients to ghcr.io/example-corp/abc? That way you could pick a new host now, and avoid images breaking in future if they disappear or if you decide to change.