If you actually study it, the discipline of marketing is actually about things like (1) the rigorous search for product-market fit, many decades before this was popular with tech startups, (2) finding ways to efficiently target and inform audiences about goods and services which absolutely add value to their lives, and which can often be extremely challenging (e.g. everyone hates thinking about death, but life insurance can be ridiculously important for your dependents), (3) developing clear, stable, predictable anchors at a company level, which people can trust and build mental shorthand for, at longer timeframes - we all have expectations for what Apple products are "about", for example. These are all absolutely vital market functions.