...if 'cable directionality' was measurable...

If it was, then it would have been measured by now. The fact that it can't be measured implies that either it is literally negligible (i.e. does not exist for any practical purposes) or that it actually doesn't exist at all.

I know that your next argument will go along the lines of 'But current science can't explain everything', implying that some future scientific breakthrough will prove you right.

We've been here before elsewhere, Mr Bennett. It's nonsense, as before.