Natural Join — Relational theory and SQL

Question

This question comes from my readings of C.J Date's SQL and Relational Theory: How to Write Accurate SQL Code and looking up about joins on the internet (which includes coming across multiple posts here on NATURAL JOINs (and about SQL Server's lack of support for it))

So here is my problem...

On one hand, in relational theory, natural joins are the only joins that should happen (or at least are highly preferred).

On the other hand, in SQL it is advised against using NATURAL JOIN and instead use alternate means (e.g inner join with restriction).

Is the reconciliation of these that:

• Natural joins work in true RDBMS. SQL however, fails at completely reproducing the relational model and none of the popular SQL DBMSs are true RDBMS.

and / or

• Good/Better table design should remove/minimise the problems that natural join creates.

?