and how do you access those computer systems without a military ID, or a DD-214? Unless you do 20 years and retire you turn in your military ID upon ETS.
On the civilian side, you need a certified abstract of birth, (not a hospital birth certificate), ID, proof of address etc to get a replacement drivers license.
I recently renewed my passport. Because it had been too many years I had to start the process completely over despite having the old passport. Certified abstract of birth, old passport, retired military ID copy, drivers license copy.
In most cases, you start with the application for your DD-214. A one-page application providing your service or ss number and dates of service gets you a certified copy of it in about a week, possibly two. While some people have run into problems, most do not.