I have worked on several very large codebases for companies you've heard of in which mutable state, OOP and inheritance are used very heavily over the years. Its not a strawman - it has, despite everything I find wrong with it, generated working systems. Granted I've found them very bug prone and difficult to change compared to others, but there's very large sets of code and coders out there who use it all the time. Its also literally taught as if its a fundamental building block and thats what people will be using all the time.