Read this. It never says that creating the product is a part of marketing. It says that marketing is given a product and specs and told to sold it, and then they have to design the marketing campaign around that product. That is a reasonable definition of marketing and the 4 P's, yours isn't.

https://www.investopedia.com/terms/m/marketing.asp

> Product > Product refers to an item or items the business plans to offer to customers. The product should seek to fulfill an absence in the market, or fulfill consumer demand for a greater amount of a product already available. Before they can prepare an appropriate campaign, marketers need to understand what product is being sold, how it stands out from its competitors, whether the product can also be paired with a secondary product or product line, and whether there are substitute products in the market.