Perhaps that's the problem? Surely they use a version control system that allows them to branch off of older commit for these kinds of urgent patches.
A lot of people don't reboot their systems. They build new ones, shift workloads and traffic over, and decommission the old ones. I can do that multiple times a day if required with no disruption of services.
You don't have to stay patched if you judge the risk doesn't make it worth it, but Ubuntu is pretty much the only distro that made the choice for you.