I do really like JavaScript's ability to compose objects like that, and I feel that people interested in it as a language should definitely learn how to program in that manner. However, I suspect that for most people JavaScript is a means to an end, and it's more useful in a number of senses to try to write JavaScript more like other class-based languages. I mean, I feel like things like TypeScript sort of miss the point of having a dynamically typed language, but there is a solid case to be made for features like strong typing, especially as size and contributors go up.