I'm glad you had such a great experience.
When I first went to Japan in the 1970s, people were already moaning and groaning about how expensive it was, but you could get a full meal for US$4 in a neighborhood restaurant, which was comparable to U.S. prices at the time.
In the mid-1980s, the popular U.S. program 60 Minutes did a trip report about Tokyo in which they clearly did everything the most expensive way possible (taking a cab from NRT to the city, ordering a Western-style bacon and eggs breakfast in a luxury hotel, gawking at the $80 gift melons and the $5,000 dress kimono, etc.).
Half the population of the U.S. must have seen that program, because since then, whenever I have an upcoming trip to Japan, someone invariably asks, "How can you afford that when it costs $200 to get to the airport?"
I think the rest of the rumors of Japan as outrageously expensive come from backpackers who have been traveling through Southeast Asia for months and suddenly find themselves back in the First World.
Some things are outrageously expensive in Japan, most notably recorded media. Even in the 1980s, a prerecorded cassette was about US$30, and although I've been tempted by some of the DVDs available on Amazon Japan, I'm put off by the prices, which average well over US$100 for a TV series. Apartment rents, especially with the key money system, and real estate are expensive, too.
However, the types of expenses that travelers are likely to encounter are about the same as in North America and may be less than in Western Europe.