The same way humanity has done for thousands of years? Word of mouth and reputation. This isn't a new problem, what's new is the ubiquitousness of advertising and the amount of money that gets pissed away on marketing.
So what ends up happening is that local businesses don't get any of the marketing opportunities which get bought out by big businesses with a large ad spend budget.
So what ends up happening is that local businesses don't get any of the marketing opportunities which get bought out by big businesses with a large ad spend budget.