Not Always The End Users Fault Wireless security is extremely confusing for normal people who have real work to do. Many of the people on this website are hardcore computer-nerds who live for these types of insecurity revelations.
Manufacturers need to make it easier to enable security, as well as deciding what type of security to use.
WPA, WEP, etc, etc... all of those are incredibly confusing and the standard firmware for WRT54G gives no information on the pros & cons of the various password protections.
Each router should have a UNIQUE default user/password printed on the packaging, just as Windows CDs have a unique product key. Of course this would be more expensive for manufacturers, but many might agree it's worth the extra cost to live in a safer wireless world.
Only those with some seriously old hardware (or a nintendo DS) would run into that, though. Consoles (I forget, does the Wii support WPA?) and portables aside the lowest common denominator these days is WPA/TKIP, which was the best my old G3 ibook supported.
Windows XP with SP3 supports WPA2/AES, and older Windows don't give a rat's ass and just let the third-party software handle it. (Thus my Win 2k picturebook's ability to do WPA2 as well )
A wireless set up wizard could be as simple as "Do you have a Nintendo DS and want it to be able to surf?" which would set WEP or WPA based on the answer. The next question would be an unskippable demand for a password, though for WEP the password would be used to generate a hex string to use for the key.
The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon profitable cause...