Just Listen to Dok's codec during that fight - he gives a sound explanation.
This. Codec conversations point out how it would have been a massive publicity boost for the Exelsus series, explains what it actually is, how it was likely never supposed to attack Raiden in the first place since he wasn't supposed to actually make it on time, and how it allowed Armstrong to still take part in the destruction without being seen.
They are the size of a battleship and probably cost billions to make, and a single enhanced cyborg with a sword can slice it in half like butter and toss it around like a toy. Not very cost effective, and
it was kinda silly for armstrong attempting to kill raiden with that big clumsy metal gear excelsus and have it chopped to pieces when he whopped raiden's *** with ease bare handed and broke his sword like a twig.
Do you honestly think the average Cyborg would stand even the slimmest chance against Excelsus?
Yes Raiden was able to beat it, but he had bleeding edge tech, heavily honed innate skill, and a lifetime of training.
And honestly I think that was a initial prototype model, did you see the size of it's chassis? It could be outfitted with a ton more weapons that it had in the fight against Raiden, gun turrets, missile pods, more lower caliber beam weapons, if fully outfitted it is easy to see that thing taking on a entire army.
Raiden is probably more expensive than that Metal Gear as well.
Metal Gears are MORE cost-effective than the pinnacle of cyborg tech. Against that stupidly-expensive cyborg, anything but another super-cyborg is going to lose in a straight-up fight. But Excelsus would easily destroy an army of Gekkos, tanks and regular cyborgs a LOT faster than Raiden ever could.
Well, tons of the optional codec dialogues delve into this. They didn't really have the technology for cyborgs to be commonly used. Cybernetic enhancements were expensive and generally limited in number. Thus, they had to use stuff like Metal Gears to do the job. First it was bipedal tanks (like REX), but then they developed technology for UGs, which developed future RAY models. Now that SOP is gone, cybernetic technology has spread like wildfire and became more affordable but still expensive. And they say that cyborgs are so rampant and pretty much normal now in warfare, so UGs and Metal Gears in general are becoming outdated due to how large and cumbersome that they can be.
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