It's not that a crazy idea if you take into account all that would cost migrating to modern Windows versions. I don't think those big enterprises/governments that stay on XP are just lazy, but instead the numbers favor this decision. Just in a quick review, consider that a migration would imply:
-Testing existing systems on new platforms.
-Modify or develop new ones for those that don't work (remember that Vista introduced many new incompatibilities).
-Stop work for install new OSs, meaning lost productivity.
-Users have to adapt to the new OS, specially non-techy people can have a hard time until they get to work again. Means more lost productivity.
-Monitor the new systems until they're known to be stable.
-Older hardware may need to be update too (Vista+ are much more resource demanding than XP). Ie more money spent.
-Purchasing licenses for a lot of computers, that alone could cost more that pay MS for extra maintenance.
-There may be simply no real reason to change what currently works fine. Specially for non-internet facing machines, the risks of using XP are minimal compared to newer systems. For servers there will probably be stronger reasons from an IT standpoint for anticipating a migration.
All in all, people that manages the big money will for sure sum those and it's not crazy to see them chose the easy way of paying to keep the existing system in good health.
Obviously, the phase "outdated WinXP" is also wrong and sensationalist. They're paying explicitly for new updates, so at least for them, it won't outdate for a long time.