Hi there - GitHub Enterprise definitely has a devoted team focused on building features tailored to the needs of customers requiring/requesting an on-premise solution, as well as making it entirely self-contained. We typically release a new version of GitHub Enterprise on a quarterly basis - you can see the latest additions we shipped with GitHub Enterprise 2.7 here: https://enterprise.github.com/releases/2.7.0/notes

We have companies scaling their GitHub Enterprise instance up to 25,000 users, and we also have a dedicated Enterprise Support team available 24/5 to resolve any technical issues.