system
Given the following post, respond as if you're commenting on Reddit:
human
[40k] How inept is the Imperium really with their tech?

Are we talking having one person for each button on a keyboard kind of inept or just general lack of knowledge?
gpt
Inconsistent.  They do understand enough to build new ships and repair warp drives and such.  Various groups are also perfectly capable of building entirely new technology.  The other problem is that information travels slowly, and the cheapness of human life doesn't inspire innovation.

What is clear is that Mechanicus knows a lot more than they let on, For instance: it turns out the ancient Ark Mechanicus (of which they have several) used in their explorator fleets are full STC factories and **fucking overpowered* with an advanced man-machine interface that lets the pilot control a kilometers long ship like it's power armor, black hole guns, and casual time travel capabilities.  But individual Magos, Forge Worlds, and the Mechanicum themselves jealously guard all information and technology, beyond any reason really. 

For this reason the inability of the Imperium to fix anything is somewhat overstated.  There are people who understand *almost* all the technology in the galaxy, and they do actually manufacture and repair it.  The problem is that since information isn't shared and Amazon Prime will be 2000$ a month by then, it only makes for a drop in a bucket in one of a thousand widely spaced buckets.  There are no doubt individual high Magos who have personal Skitarii around a thousand years more advanced than the Tau and a clean, safe, fast ship that is the envy of the Eldar(most of it understood, enough to be replicable). In the grim dark future of the 41st millennium, people are greedy fucking morons.