Syntax changes need PEPs.  By default, syntax changes are rejected.  This is especially true for new keywords, as any acceptible word will already be in use, and hence its introduction *will* break code.

We are still having issues over having temporarily made 'async' and 'await' 'semi-keywords' (for 2 versions) to smooth out breakage.  So new keywords must enable something previously difficult.  But implementing the 'empty' idea is fairly trivial, as demonstrated in the initial post.

A third alternative is a peak(iterator) class with a __bool__ method.  I posted one once, probably on python-list.  But the extra overhead every iteration must be larger than the simple assignment, which is so fast one should not worry about it.  I suspect the flag also beats the chain alternative.
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[More opinionated than the above ...]

Calling what is easy and works today 'non-idiomatic' is nearly pure opinion and not persuasive as a rhetorical device.

The complicated rules for else-never interaction to be far more 'anti-idiomatic' from a comprehension point of view.  In any case, a flag allows easy, flexible, and precise ordering of never, something, and either-way code.