We have general purpose databases. They're called filesystems. You can literally store anything and everything you like, and hardware is ever-shrinking in cost and performance.

The problem you're dedscribing is political: How to get everyone across cultural and language barriers agree upon what the bits mean?

There is no technical obstacle to everyone accepting a universal API. In many ways, we're on our way there already. The Internet is full of standards and protocols. Yet it shunts knowledge around the world caring only of a few numbers.

It might be something fundamental, like that each aspect of reality has to be attended to by a sentience. Like every person is responsible for maintaining some part of the universal standard. Maybe general-purpose-anything is flawed as a concept, and we must come to understand that what we seek cannot be automated in a meaningful way.

Maybe in the age of Turing et al there was so little knowledge it all seemed computable. Now we're drowning in it.