Just my two cents worth. The article reads in part:
But the task force said it could not find design concepts for ground-based or on-board systems that met regulations or provided a reasonable benefit for the money it would take.
Why is this?
The medical community has a technology available that uses an electrical means of separating the oxygen and nitrogen in normal air, and it's used to supply oxygen to patients. The units I've seen for a single patient are small (about the size and shape of a canister vacuum cleaner) and roll on wheels and plug in a normal electrical outlet just like a vacuum cleaner. The units have that typical green clear plastic tube for the oxygen outlet.
An aviation unit of this type (call it an "electric nitrogen generator") could produce a continuous supply of nitrogen using the same technology. I'm sure the process does not produce "pure" nitrogen, but the oxygen content might be low enough to provide effective fuel tank inerting. A system of this type with generator and lines, could be both light weight and very low maintenance, and perhaps not very expensive.
As a side benefit, the generator could be used to supply supplimental oxygen to the flight crew during a decompression event.