We need a programming language that has a data model as its core, and has
support for physical data independence.
The desired data model would incorporate all the benefits of the present
RDM, at the least.  such a data model would probably have to incorporate the
RDM as a sub model.

The programming language also needs a highly developed process model at its
core.  The object oriented process model provides a good starting place.

Here's where I would start:

Since the time OOP became popular, the design and construction of objects
has been revolutionized.  But OOP depends on two fundamental concepts, not
just one.  In an object oriented world, there are objects, and there are
messages.  The messaging scheme of languages ranging from Smalltalk to Java
is woefully inadequate.  There has been almost no fundamental advance here
in 30 years.

In order to build on the successes that OOP has acheived,  the messaging
scheme is going to have to go through a profound shift.  When people get
around to building a better messaging scheme,  they will discover that the
fundamental question is:  how can objects share data coherently?

This turns out to be the same question that database theory began working
on, back in 1970, when Codd published.  It's in a different guise,  but it's
the same question.