I wouldn't say that most people "have" to take off for it. This is a country where plenty of people (unfortunately) work on holidays regularly, and plenty are unable to take holidays, especially people who are relatively junior at their companies. It really depends on the industry. Business is slower in the summer, but in general, it runs fairly normally, unlike Golden Week. My company discourages us from all taking vacation at the same time, especially in summer, and I didn't take a summer holiday last year.
My secretary asked my company's travel agent regarding extra charges for