Like every one has different tastes, so it is hard for restaurants to determine a portion size that will make each and every diner happy. Of course, what servers should be able to do is to tell diners if they’re bound for more food than they may be able to eat.
Here's a quote: "Perhaps others might disagree, but my general experiences are: At very fine restaurants, portion size is rarely a problem. At chain restaurants and steak houses, the portions are way too big. At chain steak houses, the portions are ridiculously big. At good to fine restaurants, it’s quite random as to portion-size, although price can be a real hint. I have noticed that restaurants that focus on sustainable sources for their food have more reasonable portion sizes. Finally, bad restaurants tend to have portion sizes that are too big...." Hopefully this can help set some expectations.
As for 798 unit & co., I would prefer to re-visit and judge for myself.