When I worked in at a hometown pizza place (how stereotypical, right?) we were told again, and again, and again by the again, stereotypically 'Old Italian Man Owner' how important 'word of mouth' was to keeping his business alive after he inherited it from his own father. That was around...2015(ish) and...well, communities are aware of the local good spots to go and visitors are left to seek out online reviews when that word of mouth doesn't reach them to make their decisions. Yeah, trolling can happen but you can also get a good opinion of the place if there are negative reviews. I'll follow with another anecdote.
Earlier that same year(2014-ish) I worked at another pizza place that was newer to the (small-ish but not really) city in a prime downtown location; throughout the 3 high schools a lot of the kids found that the owner was a piece of shit - I'll skim past the health code violations and focus on the prime thing he didn't pay his employees and as high school kids, we didn't really know how to be made whole so our option was to bombard the Facebook page, Google and whatever medium that was available to spread the word of the unfair practices of this owner to the town.
So its a double edged sword. I can't imagine the shithole would have chosen to opt-in when the reviews were used to highlight the problems.