Yeah, but if every project, no matter how small, required you to spin up and maintain a full Postgres install, surely you'd start thinking, there has to be something easier than this...

The problem with Git is the same kind of problem Excel has: everyone can (correctly) claim to only use 20% of its features, thus everyone can say "Git is too complex!". But the problem is that everyone uses a different 20% of Git; Git is the union of the solutions to lots of different problems.