Suncorp's CIO, (Suncorp are a large Australian insurance and finance company), has committed to moving to open source platforms. This is being publicised as a cost cutting measure (which no doubt it is), but I (obviously) think that its just a sensible decision.
Lets make the assumption that all software, once its deployed, becomes legacy. Isn't it nicer to have that legacy not beholden to the whims of whatever company owns the source code? For the software to have a chance to evolve (open source development models encourage a more evolutionary approach) and also to be supported (regardless of any commercial organisations providing support, long term open source has a fighting chance that someone else can support it, regardless of what happens).
Its interesting that this sort of shift to open source is now happening at the CIO level (I guess it is inevitable over time - stuff that was bleeding edge and "risky" often becomes mainstream). Obviously people are seeing that at least for horizontal software, open source is the best bet to avoid black-box legacy applications which at some point no one will know how to maintain.
An interesting quote mentioning drools:
"Even for our underwriting service, we are going to be using Drools." ... "It is simpler, it is cheaper and it is actually easier to manage if we standardise it on one platform."