As I’ve said, I do not believe that the Polaris lounge access policy (business class only) matches the quality of the lounge.
The only real difference that I see between a Polaris Lounge and a Flagship Lounge at this point is the sit down service (and even then, the food served isn’t that far above the Flagship buffet). Especially when you factor in the Flagship lounge made to order station.
United has chosen to allow the lounges to slip. Hopefully they fix that now that the D1 lounges have a wide footprint. Either that, or liberalize the access policy (1Ks in premium plus, for example).