Marketing is a skill. Just because it doesn't appear valuable to you doesn't mean it's not valuable to someone. For examples on the importance of marketing, see the histories of Tesla, Tinder, most big-budget movies, nearly all triple-A games, Wool, Harry Potter, Twilight Saga, nearly all restaurants, most tangible goods purchased in a store, cars and trucks, airlines... The point is that just making a good product isn't enough anymore; there are plenty of good products. Marketing is what makes people aware that your product exists and/or makes it the preferred option the next time they are in need of that type of product.
https://www.theatlantic.com/technology/archive/2018/06/insta...
HN discussion: https://news.ycombinator.com/item?id=17330732