With changing hardware, you have to remove no longer used services and start new ones on the fly.
Most reconfiguration for hardware is handled by udev, not by the init system. We had udev before systemd.
With changing hardware, you have to remove no longer used services and start new ones on the fly. With SysV init, you only have 5 different states.
So what? You run an init script to stop a service, A file in /etc/default gets twiddled, and you run the init script again. If the service is disabled in its /etc/default file, it doesn't run. If it's enabled, it does.
and you want to have them without the need of a reboot.
They don't require a reboot with init scripts. It doesn't look like you know what you're talking about.
The problem with SysV init and similar systems is that they don't really support flexibility.
You have way more flexibility with init scripts than you do with systemd unit files.
Every hardware change requires manual changes in the booting process.
No, it only requires changes in files in /etc/default.
You really don't understand how sysvinit works.