As for the syslog/cron/apt examples I'll share some more detail below.
- Syslog Isn't used as it's pretty straightforward to pull in ones favorite language specific log library, combined with ones favorite log tool of choice and be off to the races.
- Cron doesn't get used as it can only easily handle scheduling on a specific host. Whereas there are a plethora of distributed schedulers which will happily run commands on any number of hosts.
- Apt/yum don't get used as folks want to have their builds to be repeatable, and rely on software built in via their dependency management system of choice and deployed via fat statically linked binary.