Japan's vacuum cleaner market is bigger than you might think. About 5 million are sold a year, which could be considered a lot for a country of 130 million if you think about how long a vacuum cleaner should last. Then again, there is that age-old marketing concept of planned obsolescence. Until about 10 years ago, there was little reason to go out and replace your vacuum cleaner the way you would replace, say, a television or computer. The basic mechanism of a vacuum cleaner has never changed over the years, so as long as it worked there was never much reason to want a new one. When I first came to Japan, I was given a little red Toshiba vacuum cleaner by someone who was leaving and it lasted me another 15 years.
Since then, manufacturers have added features in order to encourage people to replace perfectly good VCs like that Toshiba: floor sensors, flea zappers (for tatami), quieter motors. Such filigree only complicates the machine, providing more reasons for it to break down. About ten years ago, the big sales point, introduced by Dyson, was the so-called "cyclone" cleaner, which means no need for bags, thus reducing maintenance costs and appealing to environmentally aware people who wanted to cut down on waste. I bought one of those a few years ago, made by Mitsubishi, and it's turned out to be a lemon. Instead of a bag, it has a complex series of compartments and a self-cleaning fan that broke down several months after the warranty ended. As a result the sucking power is diminished and every time I remove the dust I also have to take the fan apart and clean it by hand.