That's partly true, I'm sure. But the other half IMHO is that Ubuntu's LTS releases are available for free. Fedora is arguably a better distro, but the 18 month upgrade cycle is just too rapid for typical server deployments. RHEL costs a ton, and CentOS and Debian lack corporate backing.

So if I need to throw up a server right now that I'm reasonably sure will be supported for the ~5 year lifetime of the image and I don't have funding and a Red Hat sales rep already set up for licensing new instals, then an Ubuntu LTS is really the best option available.