Is it possible to remove all installed components of systemd (may the inventors r. i. p.) in ubuntu 14.04 and replace them with ... well, how it was before? If so, which packages are to be purged and which installed in their stead?
The init system I believe is the component you are referring to. There are 2 major Branches of init systems
SystemD is a child of SysV. It replaced Upstart(which was also a replacement for SysV) starting in Ubuntu 14.10. Every major distro of Linux now uses systemd as the default init system. The only one that I can think of that still uses SysV is Gentoo, and our userbase is split on the issue of adoption of systemd as the default.
The major reasons that systemd is used is for ease of configuration, and that upstream GNOME has adopted it as the default init for the GNOME 3.X Desktop. Consequently, Unity was created as a replacement for GNOME at the release of about Ubuntu 12 due to a disagreement on how to proceed between Upstart and systemd.
The short answer is No, you cannot go back to SysV, as the init system is chosen by the Ubuntu OS Maintainers at Canonical