This may be worthless info but I'm adding it 'just in case'
We found about 15 years ago that it was impossible to buy regular toilets around here, they were all 'low water.' We had always heard bad things about their flushing and we live in 'the black swamp' so no water problems. We live within an hour of Canada so we crossed the border as we heard up in Canada they still had the old style.
We went to a Home Depot right over the border and the guy there said they sell ALOT of toilets to Americans for the same reason!
I do not know the reason for the newer washers, but maybe a Canadian?