Systemd usually can't be in the same repo with other init systems/service managers (or with shims and hacks) *, while they themselves happily coexist. This is the Reason that there are non-systemd distros, not some unreasonable hate for new thing or anything.

* Yes, except Openrc, which was made as a drop-in for Systemd.

Nobody was forced to change,

Red hat dominated the market and pushed it on out. You must remember this, don't you?