#WP20 perspective (#WordPress features):
2003- WP born.
2004- Plugins
2005- Pages, Kubrick, themes, functions.php
2007- Tagging
2008- Post revisions
2009- Image editing, Trash, oEmbed
2010- CPT/tax
2011- Admin bar, post formats
2012- Customizer
2013- Auto updates, MP6
2014- Media lib
2015- Emojis
2016- Rest API
2018- Gutenberg
And yes, only so much one can squeeze into a post. But these were mostly oldschool headline features that helped define WordPress (IMO). For some, you had to be there.