The primary point the author makes is that this version of Ubuntu LTS has a kernel and init system that only it is going to be supporting for most of the lifeti

The primary point the author makes is that this version of Ubuntu LTS has a kernel and init system that only it is going to be supporting for most of the lifetime of the release. Bringing up RHEL's use of kernel versions no longer supported upstream isn't really relevant - RHEL has a proven track record of supporting a kernel with patches and backports single-handedly.