In 2019, it is easy to think we “solved” source code management (SCM), that we have it all worked out. Personally my journey started with Visual SourceSafe (terrible) followed by CVS (still terrible). I moved a few companies on to Subversion (great — had atomic commits; what a revelation). In the meantime, Linus famously called everyone stupid for using Subversion so I checked out this “Git” thing he “named after himself.”
Git brought with it a few great things: distributed version control and this superpower to do things with branches and merging (in the past this was a bit terrifying).