Anything involving Kobe beef in the US has a very high chance of being a scam, since it is not a protected term. Real kobe beef is extremely hard to get even in Japan.
Kobe beef is also around $300-400 for 1kg, so maybe $50-100 in ingredients alone, in Japan, for a burger, let alone what it costs when imported.
Not that it matters a great deal. You probably still got something good. There's other highly (and higher) valued beef in Japan too, Kobe is just a big prestigious brand.
https://en.wikipedia.org/wiki/Geographical_indication https://en.wikipedia.org/wiki/Geographical_indications_and_t...
These things usually get codified in trade agreements. It seems that Japan hasn't been particularly concerned about protecting Kobe beef internationally, likely because there are so few exports simply due to production limits.
1. There is almost 0 chance that you've tasted beef from a wagyu cow from the city of Kobe. Aside from import/export costs, the cost in Japan (having actually eaten Kobe beef from Kobe) is far closer to about $400-600 per steak (2kg perhaps?)
2. Americans have been importing wagyu cattle and crossbreeding them with cows here to create American "Kobe beef" http://en.wikipedia.org/wiki/Wagyu#United_States
The average American family that even has a savings account has around $6,000 in it, total (http://finance.zacks.com/much-money-average-american-family-...). You can see how spending 1/6 of your total savings on a single meal would strike most people as out of reach.
Not to mention that ~30% of families have no savings at all.