The issue you describe seems to be related to the tools you're using and how you use them, not to the core idea itself. I've worked in several gamedev companie

The issue you describe seems to be related to the tools you're using and how you use them, not to the core idea itself. I've worked in several gamedev companies where everything was in a Perforce repository. In fact in one company EVERYTHING was in it, not just code and game data, but also documents, concept art, plans, everything. If it wasn't in P4, it didn't exist. Yet nobody thought it was a pain (after learning to use P4V at least :-P but that's a different topic) because P4 a) can handle big files just fine and b) you don't really care about the history of the entire repository, but only about the part you're working on. For example personally i had my history tab display just the engine's code directory (and even then i rarely checked it since i don't really care what Joe working on the animation code did, my main interest was on the stuff i worked - and P4V showed me both if someone else is working on the same files i am and if my files have been modified, with easy GUI tools to see both diffs and the file's development history visually - the timeline feature is honestly great for that). Perforce has some fundamental issues in how it works that creates problems, probably because of some deeply ingrained assumptions stemming from the 90s when it was first made that were never addressed, but it also has a lot of features (especially on the P4V GUI client) that makes working on a huge monolithic repository where everything goes in pretty much seamless.