I wholeheartedly agree with your main point. That said -- and I hate to be the one to split hairs -- I would argue that your Japanese citations are inaccurate.
Japanese people have and use credit cards all the time. According to the Bank for International Settlements, the number of Japanese credit card holders is roughly equal to that of Germany, and even exceeds Canada. It *is* true, however, that Japan does not have 'check cards', but this is simply because Japan does not have checks. The vast majority of cards in Japan work the system of automatically deducting the *entire* balance of the credit card once every month.
Getting a credit card just as easy as in the States. I got my first Japanese credit card after filling out a half-page form which took less than 5 minutes. No major form of identification was necessary. I get offers for "pre-approved" credit cards in my mail box every month.
Japanese people bank online constantly. Earlier this year, #2-seated cell phone carrier AU launched a partnership with Tokyo Mitsubishi UFJ Bank to access all of your banking functions over your cell phone, including balance transfers. It's been hugely popular, and other carriers have followed suit. The most profitable bank in Japan in 2004 was Shinsei Bank, which differentiates itself by essentially running an online-banking-only presence. Visiting a branch requires you to interface with your account using a PC, not a bank clerk.
Japanese people buy stuff online constantly. Last year, online sales figures per capita in Japan were only slightly below that of America.
In such a disaster-prone country as Japan, It would be short-sighted to assume that the Japanese government doesn't keep easily-backup-able electronic versions of important documents. My family registry, proof of residency, and marriage certificate are all given to me via a laser-printed document (made official by a number of stamps).
Stamps (hanko, inkan) are just as easy to copy -- if not more so -- as written signatures. Life is made infinitely more difficult for the average person as one usually has a number of these stamps in slight variations in design. They are the antithesis of simplicity. There are no records provided telling you which stamp was used for a given document. I've had documents rejected for not having the "correct" inkan, only to have the company later apologize for incorrect verification. The illusion of security is amplified by the perception among people that hanko/inkan are un-forgeable (password analogy, anyone). It is common practice for a business to accept a document from someone other than the document holder simply because it has the correct hanko. There have been numerous news stories of wives emptying their husband's bank accounts and fleeing the country.
The amount of data I push over my lines every month would *easily* be classified as "excessive use" (many times over). While it might be detected by the ISP, disconnections due to it are unheard of.
I agree with, and appreciate, the crux of your argument completely, but do not think that these specific examples from Japanese society are strong fodder.