It may very well have been two or more different people stepping on each other’s feet in the dark.
I recall binge-ing Source leak summary videos. Everything that Valve uses that engine for is extremely tightly coupled.
Whenever CS:GO or Dota 2 gets an update, data miners get to work and discover a bunch of assets of unrelated source games.
Sounds like your company is doing things the halal way and using modern standards. At Valve, it’s just a clusterfuck dev tool GUI on top of a monolithic codebase where no one can possibly know a fraction of what’s going on.