There's a vast difference between advertising a good product that is useful to hyping trash.

Good products at a reasonable price usually require a brief introduction but quickly snowball into customer based word-of-mouth sales.

Hype is used to push an inferior or marginally useful product at a higher price.

Remember advertising is expensive. The money to pay for it has to come from somewhere. The more they push a product the higher the margin the company/investors expect to make on its sales.

This is why if I see more than one or two ads for a product it goes on my mental checklist of shit not to buy.