France has been doing this in parts of its government functions for years, building expertise and learning what works. What do you imagine the EU institutions would bring to the table?
More countries and/or EU involvement could bring economies of scale: apart from translation, a lot of work on fixing bugs and adding features to the relevant open source projects can be done once and benefit all. So either get the same results faster, more cheaply per country, or both. Sure, that adds some bureaucracy and coordination cost too, but should be worth it overall.
It would be the Cathedral if it made a 5 year plan to build the perfect solution (even more so if from quasi-scratch). But the EU is also known to offer (sometimes small scale) grants in specific domains. That's much more compatible with the Bazaar.
