Open source software (beyond Linux !) has arrived and is here to stay. Analysts no longer slot Open Source Software (OSS) as unique tracks, but rather prefer to group them with proprietary software, under a specific genre. While various reports point to the greater adoption of OSS, it is the ease of deployment and the quality of code that are driving acceptance. See Future of Open Source Survey 2008 through 2015. (www.blackducksoftware.com/future-of-open-source)
With subscription models gaining ground, consumers caring about business functions and, not the technology that delivers it, the next wave of IT Sourcing augurs well for Open Source adoption. The Healthcare and Government sector have led this adoption for a while but, the others are catching up fast and exploring this as an avenue to reduce costs, re-train the IT workforce and also use OSS as the "cool" factor to attract/retain IT talent.
Many organizations have explored and exploited multi-vendor strategies, multi-shore delivery, in-house, out sourced, captive, joint ventures etc. to reduce labor costs and several others also combined automation to increase velocity of transactions. These strategies have delivered well and are now passe.
Open Source Software lends itself well to Systems of Engagement and Systems of Insight alongwith the integration and security layers. Now bring in the volume, complexity and opportunity presented by the Internet of Everything! What this does is, present us with an interesting opportunity to build Systems of Experience with great scale, minimal user training, greater access to code as well as better financial metrics.
We have to now explore OSS, get ready to cross the Rubicon  and enter whole heartedly into OSS territory.
To conclude. An IT twist - "Cry Havoc and Let Slip the Dogs of (soft)war(e)".
The phrase "crossing the Rubicon" has survived to refer to any individual or group committing itself irrevocably to a risky or revolutionary course of action, similar to the modern phrase "passing the point of no return".