I mean, some of these units had been in production in House territory for centuries by the time of the Coup, yet they never once managed to plant an intelligence officer in one of those factories to download specs and blueprints for replication elsewhere? Never made sure a shipment of certain components (or finished goods!) got diverted/lost/'seized by pirates' so they could reverse-engineer them? And they never once backed up the blueprints and specs elsewhere, so that when the factories were blown away, so was the know-how involved in building their products?
Who said they didn't manage to do it?
Actively said? Admittedly: no-one. It's inferential.
However, it's hard to avoid drawing that conclusion when you consider the fact that we've seen no evidence of knowledge or production of these technologies proliferating beyond facilities that were solely dedicated to supplying the SLDF. Or the fact that those technologies
and the knowledge-base behind them were still localised enough for the Succession Wars (and ComStar) to eradicate without knocking
every last world in the Inner Sphere back down to the level of bearskins and clubs. Being on the Internet, we all know how fast and far information can proliferate, and technical toys like DHS are memes just like any other: d'you think nuking 4chan's servers would destroy all knowledge of "All Your Base"?
Hell, the exact details of
nuclear fission were among the United States' most fiercely guarded military secrets of last century, and data-proliferation was mainly by voice or snail-mail. Nonetheless, once the Soviet Union - the U.S.'s mortal enemy of the time - had seen Little Boy and Fat Man in action, they managed to steal and weaponise those secrets in less than a decade. Less than forty years after
that, the only thing preventing
high school science projects from making a loud radioactive bang was a lack of access to fissile material!
To a certain extent, I'll grant there's reason to believe the Houses might have been, erm, 'extremely circumspect' about any visible effort to match or duplicate SLDF technology during the Star League era - between the Mother Doctrine restricting tech export, economic reprisals for IP infringements, and (inferred) black ops by Hegemony intelligence agencies nobbling House R&D, I can just about buy an effective 'lock-out' on the Houses putting THAF weapons and technologies
into widespread production and use, though whether they'd managed to get the hardware
production-ready remains open to debate. But once Amaris pulled the Coup, Hegemony intelligence had bigger fish to fry than restricting House R&D efforts, and General Kerensky actually had to give away SLDF technology
to the Houses in order to keep his forces moving towards Terra!
Hell, I can even understand the Houses holding off on duplicating/producing Hegemony hardware for their own advantage during the Civil War itself: they weren't sure who'd win, and while they knew Kerensky would have tried to annex expanded production for his own needs, there's no way of knowing
what the hell Amaris would've done to them if he'd pulled off a win.
But in the period between the end of the Civil War and the Exodus, when everybody knew that a war between the Houses was all but inevitable, when the Hegemony's bureaucracies and government agencies were gutted wrecks, when its economy was in ruins, its leadership was dead or broken, and its military was a shadow of its former self,
all bets were off... yet we have
no evidence in canon that the Great Houses built even
one new factory for
one new piece of technology prior to the outbreak of 1SW. I know, I know: lack of evidence is not evidence of lack, and they might very well have done so in places that canon carefully hasn't looked yet. (I know that's the approach I'm going to pursue in the wider universe of
The Virginia War.) But the fact remains that TTBOMK,
every canonical facility that produced advanced hardware has been specifically called out as having been built
by the Hegemony and building its equipment
for the Hegemony.
Example: the EMP-6A
Emperor, built on Menke and St. Ives since 2612. Featured technologies: XLFE, DHS, LB-10X autocannon, MPL, CASE. The Maskirovka has never been known for its reluctance to spend blood and treasure for the Celestial Throne, yet somehow, between December 2766 and the destruction of those factories during the Second Succession War - a period of more than six decades, during which those factories were
still producing, TTBOMK! - despite those factories still being in active production of
Emperors, despite the CCAF having
actual physical examples of this hardware and the production tooling to make it to work from, they never managed to get
any of those technologies into production elsewhere in the CapCon? I know the Cappies were hurting for industrial capacity, but
that much?
Example: the CTS-6Y
Cestus, built by GM on Kathil from 2766 until the factory (production line?) was destroyed at the start of 2SW. Featured technologies: XLFE, DHS, GR. Yet it's not until the incident on Hoff in the early 3020s that we have any canonical mention of House Davion experimenting with DHS technology.
Example: the
Rapier aerospace fighter, built on Tharkad since 2596, and AFAWK that was the
only factory to ever make them. Featured technologies: DHS, XLFE (Royal only), LPL (Royal only), Artemis-IV (Royal only), CASE (Royal only), MPL (Royal only). While the absence of pulse-lasers or Artemis might be explained by those items being installed after delivery to the SLDF, it's kind of hard to build a spaceframe without an engine (or its integral heat-sinks), yet the Lyrans don't appear to have built their own facilities to make DHS (or XLFEs).
Now, don't get me wrong: I'm
not advocating a rewrite of canon to show the House armies of the Succession Wars era fielding huge swathes of IS2 tech, much less of Royal-quality machines, except
maybe as an illustration of how far down the Succession Wars dragged them. Personally, I find something viscerally appealing in 'old-school' 'Mechs, despite their tactical limitations in game-play, and if the story I felt compelled to write was purely IS1 technology, I'd probably derive great pleasure from telling that story. However, the story-concept that called to me was one of exploring the reasons
why advanced BattleTech didn't proliferate during the Star League era, and what happens when external restrictions on technological advancement come off.
I'm simply saying that recent sourcebooks have revealed a lot of specifics as to how widely-spread IS2-grade battlefield technology actually was before the Succession Wars, and that wide spread has logical implications for the technological progress of both weaponry itself and of the greater BT universe. Anyone wishing to write a BT alternate timeline - particularly one with a point-of-digression before Operation Holy Shroud, like mine does in the stories of
The Virginia War - needs to be aware of that technological proliferation and the impact it could have on the development of your timeline. Whether any given writer chooses to incorporate such a spread of technology, or find a way to write it out again and go back to 'old school BT', is a creative choice they must make for themselves.
Or they could just say "LOL logic =/= BattleTech ROFL" and write about big stompy robots blowing pieces off each other.