>>23584333
Much like the kajillion Zaku variants I think it's the EF equivalent of trying to solve certain problems and as such only making a tiny handful of particular prototypical units, only to abandon them for reasons related to performance, cost, complexity, or mounting evidence of obsolescence. The EF is run by old farts, so it'd also make some sense that they'd try to keep the idea alive even if evidence was mounting that it wasn't salvageable.