There are three professions where being untruthful is the key to success: Lawyers, salespeople, and marketing. All three are hired to portray their client in the most favorable light possible, and the very best ones lie through their teeth. The worst of these three are the marketers because they have legions of psychologists and scientists trying to figure out the best way to lie to people.
Yes! You're both presenting a perfectly defensible argument against marketing and reinforcing my original point! Because geeks tend to abhor marketing, we dismiss its significance, and are perennially gobsmacked as to why an intrinsically emotional, manipulatable species is so susceptible to emotional manipulation.
So long as humanity is what it is, reason will only ever get you so far. You either need to blow the doors off with a staggeringly amazing thing, or come to terms with the fact that every single entity who might care about your thing has feelings, and bending those feelings in your favor can work wonders.
It's not all bad, though; emotional manipulation works under much the same constraints. Unless you're a Level 80 Snake Oil Salesman with a hat full of luck, you're going to have a very hard time making your thing last if it doesn't live up to the hype--and your reputation will suffer for it.