I'm not surprised. systemd reinventing and horribly overcomplicating things is nothing new.
Different tools suit different people. Cron isn't dying any time soon just because the casual Linux user is better served by systemd.
take oddjobd for example, which supplants pam_mkhomedir.so in creating a users home directory on first login. oddjob is its own standalone daemon running constantly, while pam_mkhomedir is invoked only as necessary. oddjob needs dbus and systemd to complete what in many systems is just a simple mkhomedir && chown user:grp $homedir. its now fully dependent on the most fundamental building blocks of your OS to do one simple thing.
this also assumes the user doesnt have a home directory...which...many do.
in most commercial infrastructure if you suggest installing oddjobd to handle the potential for a user to log in without their home youll be laughed out of the chat. oddjobd forces organizations back into the 1980s and NIS based implementations of federated authentication where you had to go to a new user machine, or an account creation machine first if you dont want to run yet another idle daemon on your machine
I don't see any of that citation. Or evidence.
Just because you deem something overly complicated doesn't mean that it doesn't serve a practical purpose.
You don't want to go to all the effort to spin up a CPU core to schedule a (cron) process thread, just to find out it has no work to do. Ideally, if you're going to check the time at all, you just want it done in one thread running on one core, so that the rest of the cores can stay asleep and you never have to spend energy context-switching when idle.
That being said, systemd isn't quite the right architecture for getting down to a "tickless everything" system. That'd be something more like WinNT's kernel timer object API, where the kernel sends an event to your window's or service's message inbox to wake you up when the timer is done; or macOS's "Grand Central Dispatch", where any native code (including non-Foundation POSIX code!) can pass scheduling control of any async block through a Mach trap over to one central scheduling process, which coalesces both timers and the runtimes of async events in general so that all background CPU activity happens in bursts with idles in between.
Right now, I am doing this all with a mess of shell scripts (flock + logger + echo calls + pgrep). This is fragile and ugly.
Since systemd provides all of the above easily, a better approach will be one-off systemd jobs. In this case, my crontab entries would be a trivial -- "1 3 * * * root systemctl start cronjob1". This only requires scheduling functionality -- background execution, env vars, email notification and other things no longer matter.
From there, it is just one small step to move scheduling into the init process itself -- after all, compared to what other things init does, scheduling is both simple and safe.