Create a proudct so good people would feel stupid for not buying it

When you try to buy a certain product like toothpaste, there are hundreds of options. If someone creates a feature that only their product has that means, there are no alternatives and if it’s good enough you won’t need to spend a lot on marketing? Why? Because a new valuable product that has something never seen before will gain fame from people who buy the product. The people who buy the product will tell others to buy it.