This is the over the top hyperbole the OP was talking about. Even if systemd did "replace Unix", I don't know why anybody should care.
As a long time Linux user it's clear that Systemd took over because it's better. The old way of doing things was a complicated mess that had evolved over decades, and was difficult to use and understand, with lots of weird interactions and no consistency.
Having a standard way to do admin tasks across all of the distros is valuable and makes Linux easier to use and more reliable.
This is the over the top hyperbole the OP was talking about. Even if systemd did "replace Unix", I don't know why anybody should care.
As a long time Linux user it's clear that Systemd took over because it's better. The old way of doing things was a complicated mess that had evolved over decades, and was difficult to use and understand, with lots of weird interactions and no consistency.
Having a standard way to do admin tasks across all of the distros is valuable and makes Linux easier to use and more reliable.