Engineer 3 "It doesn't look like a Sherman, isn't built like a Sherman, and was designed by the Italians. So why are we still calling it a Sherman? And why did we prioritize it over our own cutting-edge R&D?"
Inner Sphere manufacturing didn't rise to Star League quality in the 3050s, sure. TR:Project Phoenix does say that its 'Mechs use fancier tech and have new appearances, but I don't think it mentions quality of manufacture, and the FedCom Civil War & Jihad both make a lot of noise about harming everything to do with manufacturing. What makes you say quality
rose? More to the point of this thread, it seems to me that 'Mechs optimized for the "modern battlefield" might not scale well to Star League levels of production and organization. (That's not the theory Catalyst went with, but it's as good as any other.)
(Nitpick: individual MechWarriors swapped weapons on the
Ostscout,
Scorpion,
Ostroc and
Thunderbolt; a few weapon swaps on the
Crusader (and maybe
Shadow Hawk-5D) come as kits; the rest of TR:3050's unseen variants were factory only. Not kits. /
EDIT: The post-Tukayyid mercenary market did have the rest available as kits, but we're looking at what the Houses built for themselves.)
Some of that can be attributed to the downscale, but also things like the Tricentennial Attacks.
Downscaling seems to have been relatively inconsequential outside the Republic. Tricentennial Attacks may have done more damage, but weren't those mostly anti-human and anti-facility events, rather than anti-'Mech?