POI's are a tough nut to crack. I've had many many errors with google maps too.
To answer the question- is there not one place that has a list of correct POI's?
Answer- sort of, it just needs to be gathered.
IMO - the best path forward is to partner(ie pay) with local, state, or country wide entries who's primary purposes are to know and go to said POI's on a regular basis. Example - US postal service/fedex/UPS. Do they or do they not essentially go to POI regularly? So......