>>"never once seen a productionalized version of these"

YET

Just because we have not YET seen one does not mean it should not be pursued.

Examples are endless, start with: 30 years ago, no one had seen a solar panel with 25% efficiency produced for less than $1/watt. Now, it is the most economical and fastest-growing and most sustainable energy source on the planet.

That argument is simply an argument against all efforts at making progress. Perhaps rethink making it?