That's because github isn't trying to be a replacement for JIRA and source control for most teams.
Scroll down to "break issues into actionable tasks", and they have an example that's even labeled as an "Epic". They are definitely headed in the same direction as Gitlab.
I'm unsure as to whether that's a good thing or not.
1) https://github.blog/2021-06-23-introducing-new-github-issues...