If you want to be cynical about it, consider that you already have it embedded in your infrastructure. Your real value is the stuff you've built on top of it. If it's open and widely used you'll have an easier time hiring experienced people; you might even acquire a company with something new and useful to you that's built on the stack you already use; and, you know, someone might even fix a bug or add some great new functionality that you can take advantage of.
Plus if your stack becomes dominant, it's the other guys' (your competitors) problem to change their stack instead.
