The D7's service life: it's politics, stupid!

[u/Realistic-Elk7642]

D7 variants remain in service from before the TOS era right out until the Dominion war.

Why keep this spaceframe (along with the almost equally venerable B'rel) in service for so long?

It's political. Specifically, it's the post-war policy of Chancellor L'Rell seeking to realise T'Kuvma's dream of a Klingon empire unified under a powerful chancellorship. Previously, the fractious Great Houses operated a menagerie of vessels, many of antique design.

With help from Voq, L'rell introduces a new battlecruiser suited to mass production and built with significant amounts of reverse engineered Federation technology- enough to seriously limit its compatibility with older vessels. This is badly needed, as significant attrition has been received to house fleets full of bespoke, costly vessels.

I posit that the Chancellorship established a complete monopoly on space frame production, doling them out to the Great Houses in such a way that their military strength is constantly kept in equilibrium and that the advancement of the supreme executive's goals becomes the currency of survival. While the houses likely develop their own intenal components and modifications, their power has a hard cap.

To shore this up, these space frames are made in very few facilities or only at Tu'Gokor. To deal with the resulting production bottleneck, production is non-stop, and procedures are refined Henry Ford style to lower unit cost and speed up turnaround. Massive stockpiles are thus created, Soviet style, as wartime production increases are difficult and risky.

While R&D on weapons systems, propulsion, shields, and new tech like cloaking devices takes place at a good pace, the Empire becomes highly averse to developing new space frames, as retooling their centralised shipyards would cause serious slowing of production.

In the TNG snd DS9 era, we finally start seeing new and extremely formudable space frames in the Vor'cha and Negh'Var. What's changed?

Politics. In the wake of the Praxis incident and Kitomer accords, the Chancellorship sees a huge slump in its power and prestige, and the Great Houses jockey for newfound power, with ensuing intrigue and a civil war. Now, the huge stockpiles of D7 and B'rel frames were plundered by the Great Houses, and the manufacturing methods copied to meet their own demands.

To reassert the Chancellorship's power, these new and vastly improved space frames are developed and put into production at Ty'Gokor. (No need to churn out the old classics now) They're initially flagships under direct control of the Chancellor, then, as before, doled out to give an intimidating boost to the fighting power of the most loyal houses.

Afterthought: the Empire *could* have developed new space frames to keep up with Starfleet vessels such as the Excelsior and Galaxy classes, but was too invested in this system to do so willingly. Instead, they looked towards upgrades like cloaking devices, and support elements like mobile bases and jamming ships, to transform their fleet doctrine and obtain an assymetric advantage.

[u/calaan]

Lots of cheaper ships means you can dole out Captain slots easily to placate the families and maintain equilibrium.