But then how do we justify this dumpy, piece-of-garbage looking machine with no modularity being part of the same line as these far more advanced-looking, cleaner machines that do things other than charge forward and punch crap with stumpy spiked armorarms. Also what plot reason can there be to deny such a basic, endemic mecha trope such as "older machine that can still hang". Technically even Eva did this with Unit 00 and Big O has, potentially, the Archetype and the actual main unit itself is arguably the least advanced Big featured in the series.