The only way to increase the market share of your company is by showcasing that your product is much more superior or sometimes cheaper than the others. To a certain extent, I would say the companies try to influence your decision rather than manipulation. If marketers employ covert tactics to manipulate customers, then they run the risk of being seen as unethical or may face lawsuits. The more relevant question is to what extent is the company answerable to influence people and monitor their use to target them with specified products.

Source: https://knowledge.insead.edu/customers/manipulating-consumers-is-not-marketing-4662