The United States federal government allocates a staggering $38 billion annually to prop up the meat and dairy industries. These subsidies significantly reduce the price of meat products, including hamburgers. Research from 2015 reveals that these subsidies slash the price of a pound of hamburger meat from $30 to the $5 we see today
The point seems to have gone over your head. NZ is a smaller, unsubsidised, more expensive market than the US and ground beef doesn’t cost anywhere near the $30 US per pound you are claiming.