I'd guess that most hospitals don't do in-house development for the software they use. They paid someone else for it, probably at "enterprise" rates; it's hard to blame them for not having the budget or desire to replace working systems with new shiny (complete with new bugs) every X years.
...are how the state-of-the-art is advanced in other industries? Imagine if the FAA's response to an air disaster was, "Never mind root causes, you just should've bought a newer plane".
With that the GSN (Government Secure Network) is still a good ring-fence (that's outsourced as well) but once something gets inside, boom.
Now with the Trusts - they do have a local IT bod and in the cases I dealt with, somebody who knew how a PC works and enthusiastic, which is nice but also dangerous and I had to deal with a few issues that were as I call them "enthusiastically driven". As such you have all these Trusts operating at some level as independants and with varity of results.
One case, was one `IT manager` at a Trust who was posting on a alt.ph.uk (UK hacking usenet group) and offering up inside information about how they operated. That did not happen as the alt.ph.uk lot are a moral ethical lot and health services are taboo, so was rightly shot down and equally the chap was soon in talks with security services.
But with so many legacy systems, and an event driven support mentality (again Y2K being an exception) then such events can and will happen. Sadly many trusts lack provision to handle such issues and as with many IT area's are event driven instead of being proactive. Indeed ITIL the golden managment love-in solution for support management is event-driven and many an implementation ticks all the ITIL boxes of compliance and yet still lack proactive support. This alas is mostly gets compared to firefighters pouring water on buildings so they won't catch fire and sadly pretty darn systemic in many an organization.
With that the best anybody in IT can do it to flag up an issue in a documented way to cover there ass then the outlined event does transpire to prevent unfair scapegoating. A sad situation of which many of not all IT support staff in all capacities can attest too.
Ironicaly DOS based legacy systems with no networking and exitic ISA cards in some equally over-priced hardware still work and the need to replace them does become moot, alas that example gets projected upon other systems that are networked. But the whole health industry has many legacy setup's that are expensive to replace, more so if they work and the motivation to limit potential damage from future events above and beyond backup's becomes a management issue that lacks a voice for budgets.