Of course navigation controls are unique to each title. Supposedly, Disney's Tarzan has 4 minutes of trailers which can't be skipped, but can be fast-forwarded. DeCSS is the first DVD ripper. While some have gotten it to work, it will crash and hang many PCs and is probably incompatible with many combinations of ASPI drivers and drives. DeCSS, when it does work, only allows the user to extract unencrypted VOB files, which lack the program and navigation elements of the original DVD title.
Region coding is one bit on the disc, which the player checks.
Subtract that from the 100s of operating systems in existence. I'm not sure what the specs are, but I believe the region control can be set a maximum of five times by the consumer, and this maximum can be reset up to 4 times by a lisenced service provider. I don't know which is the better tack. Listing the OSes where DVD is not native shows the hoops some licensed users have to jump through. It's not an encryption system, it's just one byte of information on the disc that the player checks.