Tangentially, is there something implicit about class hierarchy and game development? Most engines and libraries are built on deeply-nested, hard to follow, inh

Tangentially, is there something implicit about class hierarchy and game development? Most engines and libraries are built on deeply-nested, hard to follow, inheritance models. I read about entity-component systems, but there's seemingly no big, functionally-oriented game engines. Why? Legacy? Typical languages (C++, C#, etc.)?