Of course Japanese do not eat Japanese cuisine everyday. May be the dining at the authentic sushi bar is decreasing than before. Especially young Japanese prefer western cuisine rather than typical Japanese dishes. Consumption of beef is higher than the last century.
Beef is imported from either US or Australia. US was the biggest meat exporter to Japan but drastically decreased when mad cow disease occured. Since 2004, Australian beef has nearly 50% of market share in Japan.
Large hamburger chains use patties made of Australian beef but many cozy restaurants use US beef. It seems that people consider as Australian beef = cheap and US beef = luxury.