"I can think of many products that failed essentially because no one heard of them and not because they were too expensive."

Products don't fail because no one has heard of them, they fail because no one buys them. It's your job to go out and find customers; waiting for people to hear about you isn't a strategy, it's a 100% guaranteed way to fail.

Real entrepreneurs figure out their customer acquisition strategy before designing and building their product. Those who do it the other way around aren't entrepreneurs, they're just hobbyists. Read Four Steps to the Epiphany, Crossing the Chasm, Bootstrappers Bible, etc.