Then there's the expense. Ah, you say, Larry Ellison of Oracle will give the govt the database software for free. But he will charge for maintenance and upgrades. Besides, the major cost of a database is not the software. That's actually a tiny portion of the cost. Requirements analysis and design are far more expensive. And think of all the govt data entry people you'll need. The people to verify that everyone with access to the database is actually entitled to access. Etc, etc.
And access: to be usable on a national level millions of govt people would need access to your data. Does none of this concern you?
Even if we don't manage to spark a movement for a Constitutional Amendment, it will come in handy for dealing with those on FR whose Cult of Personality has clouded their better judgment where trusting the government is concerned.