It depends on the context. Yeah it'd be lovely to have your system connected to the internet - but no, our clients wouldn't give us money if you do that, and we need money. So, maybe yes in this case, start writing some quality, well thought out maintainable libraries (that can include audited third party code), and just bill it. In my case, the cost to the client of a team of devs working on that was less than the cost to them of the risk of a film leaking...
[Edit] - But what I have found through experience is that the code that was written under these constraints seemed to be better, more secure and robust, than without them. YMMV.
[Edit] - But what I have found through experience is that the code that was written under these constraints seemed to be better, more secure and robust, than without them. YMMV.