EL wire brightness, per m not per m\$^2\$
Wire does not produce light one-dimensionally - it produces light in all directions and the intensity of the light is maximum right at the surface of the wire.

Imagine the light is emitted in all directions along the length of the wire - there is real power entering into the space between the wire and your eyes and, at any particular distance from the wire, the sum total of that power remains the same (just like it is on a radio antenna).

What happens at a greater distance is that the power per sq metre reduces because the surface area that the power is passing through gets bigger proportional to distance squared.

This is why the lumen per metre does not really mean anything. It's lumens per sq metre.