The difference between inittab and the scripts controlling the startup routines are minimal. A person in 2005 could grasp the difference between BSD and Linux init scripts in about an hour.
As for hating systemd, that battle is lost, my friend. There's really no point in even engaging any discussion about it beyond this paragraph. No one is looking to write shell scripts for init in 2020 when there are systemd service files that are simple configs. It's provided by the distro, that's why it's adoptable. No one in the right mind trusts open source project devs to maintain compatibility in even minor version variations, that's why there's a booming container business. Tools that the distro provides work, tools from third parties are on borrowed time until they break, so yes systemd is the only viable up-monitoring solution.