Being able to schedule posts being published and unpublished has been 'core' territory for (proper?) content management systems for at least 10 years (to my personal knowledge as a former corporate IT Director).
While I understand the origins of the application and continue to use it enthusiastically for client sites, it's about time WordPress caught up.
I remember years ago the car makers in the UK saying air-con wasn't available because no one wanted it. When something IS available (without it being a retrofit which may or may not work with your model/release version), it's surprising how many people find they'll use it.