New Yorkers have decided to keep buying stuff brought on these trailers. You probably have too. People voted with their wallet and decided they would buy the goods that came in on the trailer. The reason is because it's just way more practical, and cost efficient, to go along with the standard the rest of the country is using.
Until 1997 Hong Kong was a possession that functioned much like its own country. NYC is simply incomparable to this situation; NYC is less than 5% of the country. I'd also note the tariffs and regulations on goods coming into Hong Kong were way more liberal than NYC before the handoff, so Hong Kong as able to withstand some higher ground transportation cost than NY can withstand at same price.