I actually have the opposite opinion.
In game development we care a lot about build systems- and annoyingly, we have vanishingly few companies coming to throw money at our problems.
The few that do, charge a kings ransom (Incredibuild). Our build times are pretty long, and minimising them is ideal.
If, then, your build system does not understand your build-graph then you’re waiting even longer for builds or you’re keeping around incremental state and dirty workspaces (which introduces transient bugs, as now the compiler has to do the hard job of incrementally building anyway).
So our build systems need to be acutely aware of the intricacies of how the game is built (leading to things like UnrealEngine Horde and UBA).
If we used a “general purpose” approach we’d be waiting in some cases over a day for a build, even with crazy good hardware.
If you're at a games studio that values build-times, value that. I worked at a very good SRE-mindset studio and missed it, deeply, after I left. Back then I expected everyone to think and care about such things and have spent many, many hours advocating for best-in-class, more efficient, cheaper development practices.
WRT github actions... I agree with OOP, they leave much to be desired, esp when working on high-velocity work. My ci/cd runs locally first and then GHA is (slower) verification, low-noise, step.
Also game dev here - I disagree with your take. Our _build tools_ need to be hyper aware but our CI systems absolutely do not and would be better served as general purpose. What good is Horde when you need to deploy your already packaged game to steam via steamcmd, or when you need to update a remote config file for a content hotfix. Horde used BuildGraph meaning you need a full engine sync’ed node to run curl -X POST whatever.com
Game dev has a serious case of NIH - sometimes for good reasons but in lots of cases it’s because things have been set up in a way that makes changing that impractical. Using UBA as an example - FastBuild, Incredibuild, SNDBS Sccache all exist as either caching or distribution systems. Compiling a game engine isn’t much different to compiling a web browser (which ninja was written for).
I’ve worked at two game studios where we’ve used general purpose CI systems and been able to push out builds in < 15 minutes. Horde and UBA exist to handle how epic are doing things internally, rather than as an inherent requirement on how to use the tools effectively. If you don’t have the same constraints as developing Unreal Engine (and Fortnite) then you don’t have the same needs.
(I worked for epic when horde came online, but don’t any more).