A nice compromise would be to open source the libraries that consume and emit data as well as core processing. Then they can add their own secret sauce UX and integration.
Yes, they used to compromise more along these lines in the past. e.g., Samba's vfs_fruit would never have gotten as good as it is without Apple open sourcing their SMBClient. Everyone benefits, even Apple (I'm sure they're running vfs_fruit on their server storage arrays internally). Wish they'd do it more.
I wish they open-sourced their built-in macOS apps.