Surely the 6-feet/2-metre spacing cannot be maintained when pax need to visit the toilets, or wait for toilets. Also cabin crew will continually pass close to pax in aisle seats. I can see the spacing work after a fashion in 2-4-2 becoming 1-1-1, ditto for 2-3-2. But to achieve a practical yield, airfares would need to increase by up to 65%. And more than double, on single-aisle aircraft. Another solution will need to be found.