Set up your docker file to be part of your CI so that your binary blobs are built from source with regularity? That’s typically the solution I’ve seen work well. Manually maintained stuff (especially for stuff that may not be the thing everyone is primarily doing) generally doesn’t scale well without automation (speaking as someone who’s seen organizations grow). This is also true of “getting started” guides. Can’t tell you how much maintenance and run time I’ve saved converting those wikis to Python scripts.

Yes, of course. That would be ideal. That's what we do for everything we can control.

But as someone in the IT dept., far too often you get some container that either was built by someone who long left the company or an external consultant who got paid to never return. Sourcecode is usually unavailable, and if it is available, will only build on that one laptop that the consultant used. The IT department gets left with the instruction "run it, it was expensive" and "no, you don't get any budget to fix it". That results in the aforementioned containers of doom...

Yes, I'm bitter and cynical. Yes, I'm leaving as soon as I can :)

I hate to raise a seemingly obvious point, but this doesn't seem like a problem with Docker.

In theory that works. In practice it rarely does. Docker et al gained popularity because they made it way more practical for projects to be managed as the world works rather than as it should be, for good or ill. Before Docker it was moving old applications to VMs and before that it was running them in chroot horror shows.

> the hardware lifetime "naturally" limits the lifetime of such applications

Oh, my sweet summer child. Of all the things that "naturally" limits the lifetime of such applications, that is not it. Consider the case of the mainframes running the US banking system, for example.

Can still remember the multinational were wanted to host the webapplciation we developed from them at their data centre. They wanted to charge us (not the business unit for some odd reason) nearly €20.000 per year to host a RoR web application.

Ended up, hosting it ourselves, and in the last year they were paying €100k per year for it. As we would just sell the same setup for each deployment for their customers. They probably been cheaper off to host it themselves.