Software is a Liability not an Asset
As told to me many years ago by Paul Everitt, then CEO of Zope Corporation:
"Software is a liability, not an asset".
(unless of course your sole business is actually developing software, but that is only a small minority of companies)
It amazed me working in a high street bank, just how much software they had written in house for general admin stuff (I'm not talking trading here, I'm talking general business process stuff). Most of it the orignal author had left and no-one knew how it worked. Yet at the same time they were vary wary of Open Source, as they thought it a risk... HELLO??!!
I managed to get them to at least switch to an Open Source content management system for their Intranet (Plone) but they still very much had the culture of keeping things under their belt. It wasn't the developers as such, but more the management. If anything was to be released outside the bank then they'd need to get their legal department to take a look at it (which invariable didn't know code from a cucumber) and so the process would just stall.
They in the end ended up with an internal fork and a lot more maintenance than they would have done had they been able to commit their work back to the main community and not have to maintain it all themselves.