The following is not exactly highly academic EAI design pattern discussion, be warned. Don't read if you value your time ;-)
Another thought from everyday life. Ever had to deal with power plug interoperability? Well I had, especially when going to UK and US (I'll not even mention Poland: they have an exotic ground pin that comes out, instead of being an hole!). Those adapters are the first thing you should shove in the bag when you plan to go abroad with the laptop: failing to bring them along results in buying them twice, typically you find them only in airports and they're surprisingly expensive for being just a bunch of plastic and alloy. But the MOST frustrating thing is when those adapters are not enough anyway! The leftmost item is my laptop power plug: note the ground pin in the middle. Well, the off-the-shelf adapter set doesn't have the hole for my ground! And digging a new one is not easy at all, nor getting rid of the groud pin on the laptop plug is a good idea, since everything is embedded in a single piece of plastic. The custom solution is the third item from left to right: a trivial italian2italian adapter on which I got rid of the central pin. Sadly, I could gather the equipment for this solution only AFTER being back to Italy (however, that happened years ago; at this PDC I had my custom adapter set ready, though I managed to leave it in the hotel room at least once...).
Now, think how easier (and more economic! After all, people from Genova are famous for being very aware of the money they spend) all this could have been if only everybody would agree to a single set of power plug interfaces... hey but wait? Doesn't that remind you of something that is going on right now in the SW industry? (hint: locate the string mande by the two last adjacent capital letters and reverse it ;-))