LTS releases were made to be as stable as possible (or at least moreso than later versions), and one of the best ways of doing that is to use older, less experimental, less unstable versions of software.
They were made for people who want something that works, and something that will work and be supported for a long time, hence the term "Long Term Support". It would be annoying to install this brand new spanking distro, only to have to upgrade a couple months later because your current version is lacking support and updates.