Would you think a business would change their dining policy because of a couple of outliers? If there was a charge for multiple meals, then those people would just switch to the Lido and perhaps eat more?.
We share a hamburger at Red Robin for lunch. On the road we have share a 12 inch subway, and drink most of a bottle of wine. We are 74 and seldom eat as much.
On the one gala night they have lobster tail, we often will ask for a second. We seldom have lunch on a cruise, and find that the 4-5 oz. tail now served is not much different from the 10-11 oz one they served some years ago, only when you order two. We only have rice with it.
I, not my wife, have been known to ask for another short rib on that night, but not another meal. The deserts are too rich, so we normal each have ice cream. Most of the people on HAL, at least the longer cruises, are even older that we are (on average perhaps another 5 years). It is seldom I have seen anyone ask for a second meal, except when the first one was poorly done, or not as advertised. The everyday steak is often to tough for me to eat.
HAL must have observed more of what you saw, than what I have seen to take such a drastic move. Maybe on the shorter cruises, with many more younger people multiple orders are more common? We are 4 star with HAL and have just not seen this as a problem. More we have seen HAL service eroding, and there offering degraded. They have allowed there ratings to fall off seriously. Are they becoming Sears on the seas?