[ChadNauseam]

In many cases this is the opposite of true. GTA online had a bug in their home-rolled json parser that caused it to read files in O(n*2), which went unfixed for years and added minutes to the loading time. That bug is much less likely to exist in a popular open-source package, because there are more eyes to catch it and fix it.

[llanowarelves]

Yep. Game devs handroll lots and release back to public much less than other tech companies. Not unheard of to even forego c++ stdlib and rolling their own structures.

In these cases it's not a matter of not understanding the low level internals.