Nobody programs in machine language or binary anyway. Someone in house puts together an engine or set of tools, based on the needs of the development team, and most things after the fact are done through those tools. If something major is needed to be changed to the engine it likely will never be done after a certain point.
This is why, for example we’ll never get a stash increase, but we continue to get skill, stat and paragon changes and even item upgrades.
The one person on the classic games team who is maintaining D2/D3, Star Craft 1/2 and the hand full of other old games, yes including the seasonal updates for Diablo 3, is not coding a damn thing; and if he is, it’s in a scripting language module within the engine/tools. Trust me, they don’t get paid enough to know the sh*t you’re talking about. 
Many modern games from “not Billion $ companies” use prebuilt engines with addons and mostly script and GUI their way through creating games these days anyway. They might hire one guy to make some major modifications to an engine, to facilitate a new feature that nobody has thought of yet, but for the most part it’s much easier, faster and cheaper to do it through engines and tools. That’s why games are super bloated. You ever wonder why GTA online is over 150 gig? 
This ^ exactly.