There's already an open standard for the core functionality of code hosting sites: Git. Projects migrate between GitHub, GitLab, Bitbucket and other alternative

There's already an open standard for the core functionality of code hosting sites: Git. Projects migrate between GitHub, GitLab, Bitbucket and other alternatives all the time by simply changing the Git remote. There's some lock-in via extras like issue trackers and wikis but that's not difficult to migrate, especially with Markdown as a common standard so markup can be preserved. I'm not really sure why you think that's relevant to this. Google Code simply failed to compete with the alternatives and was obsoleted. It has nothing to do with lock-in.