The sentence for preferring "composition over inheritance" for code reuse is in the book by the gang of four (the design patterns book). I really don't understand how we ended up in the situation, where 30 years old advice is still valid and still not followed. I lay, perhaps too much, blame on Java, which seems to have this baked into its infrastructure, but similar approaches have also been adopted in C++ with multiple inheritance making things even worse.

I mean, SOLID, when used appropriately, is also valid. The problem is that the design patterns are used where a simpler solution would work just as well.