Well, I spoke too quickly about the wikipedia article then. It must have changed, or I've read another page. The page which says that is wrong. Communicating product value is only part of the marketing mix.

Building a great product is most definitely part of marketing. For example there are methods and techniques which faciiliate it and are subject of marketing journals and marketing academia. One of these methods is the "segmentation-targeting-positioning" framework.

I can get you many more citations if you wish, or you can spare me the time, and search for them yourself. Perhaps you will learn something of value in the process.