This is a hard business problem. I believe the only way is to have this business inside of another business entity where reviews are not the profit driver but contributes to value of the entire business.
That's why I see only Google Reviews to be in the best position in this category. It is not perfect but way way better in terms of incentives etc. compared to Yelp and its ilk.
It's primary value for Google is the huge moat that it provides against Apple maps where Apple is dependent on the crappy Yelp reviews. I say crappy in the sense of terrible incentives as mentioned in the OP I am replying to. This poisons the whole review system of Yelp and Apple maps by association.
That's why I see only Google Reviews to be in the best position in this category. It is not perfect but way way better in terms of incentives etc. compared to Yelp and its ilk.
It's primary value for Google is the huge moat that it provides against Apple maps where Apple is dependent on the crappy Yelp reviews. I say crappy in the sense of terrible incentives as mentioned in the OP I am replying to. This poisons the whole review system of Yelp and Apple maps by association.