I haven't worked in video games since the PS3/XBox360 but everything was bespoke on every platform for every game except for maybe low level audio in my ten yea

I haven't worked in video games since the PS3/XBox360 but everything was bespoke on every platform for every game except for maybe low level audio in my ten years on PC/Mac/PS3/XBox360 and I had to review/examine code for games other than the titles I worked upon. Even games that used game engines/physics engines have heavy customization. I only worked at smaller studios but the practice of starting from almost scratch every time can make it hard to have a standard toolkit of AI, the reuse incentive was low.