IMO, docker layering over the OS's built-in package management and update lifecycle in an incompatible ways is far worse than systemd replacing the init system and other service management functionality.

Back in the old days (late 90's, early 2k's) as a sysadmin I'd often write scripts to chroot or in other ways isolate services rather than run them as root, so extending the init system to handle those features feels like it's a logical extension, not a incompatible replacement.