Board Thread:Warhammer 40k General Discussion/@comment-25149066-20140730083800/@comment-6078851-20140806151536

they can preserve it, to a certain extent, but they don't have the knowledge to repair it which is what is currently needed. to use a car analogy: for a non-mechanical engineer a car engine can be maintained by keeping it clean, checking oil pressure, replacing oil, etc, but if the flywheel gets a crack then they can't do anything other than trying to keep it running until the flywheel breaks, and without the proper mechanical ability it will break.

this is the problem with imperial technology, most of it can be maintained and even repaired to a degree, but most of their high-technology is made in factories by machinery, and if/when production machinery breaks down it can't be repaired or replaced easily, and sometimes not at all - some tech is only produced by a single world because that world has the only machinery left that makes this or that, and when that machine breaks the tech is then lost because they don't know how to rebuild it.