El Register reports that the Linux kernel is gaining a longer-term support model. Their article indicates that Greg Kroah-Hartman is planning on a six-year term for the various Linux kernel long-term releases.
Currently, Linux kernels have a two-year life in the Long-Term Support queue, before being retired. This support period isn’t enough for Google, who need longer-term support for Android phones, among others. The process of releasing a new phone often burns through most of the support time of a kernel. And with changes in kernel revisions mean possible code changes to support changed API calls, moving kernels can be an effort to keep the bloatware up to date.
So backporting fixes from the current kernels into the LTS kernels will improve security. It should also mean a potentially longer life for some phones. However, given the regularity (or rather not) in which manufacturers and carriers release new code to phones once they’ve hit peak market share; I think that’s not realistically going to happen.