[microtonal]

No. In addition to what saurik said, setting up a full-blown GitHub-like service for your own company/institution is not that difficult.

We use Gitblit. Since it is self-contained application, it (literally) takes just a few minutes to set up [1]. After that, the number of repositories, users, and repository size is only bound to technical limitations. I get the impression that GitLab is also pretty simple to install these days with the GitLab Omnibus packages.

And even if you want to use GitHub or BitBucket for your proprietary code, adding yet another company to the loop only increases the probability that your code will be stolen in e.g. a security incident.

[1] Perhaps also important: it integrates with internal authentication servers (LDAP, etc.).