UAC has never been a security feature. Microsoft has NEVER claimed that UAC was a security feature. It's a convenience feature that acts as a forcing function to convince software developers to get their act together.
And if you don't like the default settings, you can make a trivial change to increase your prompting level back to where it was in Vista and all these "exploits" go away.
The ONLY secure scenario is to run as a standard user (with no admin privileges) and use fast user switching to switch to an admin account when you need to make configuration changes to the machine. But most users won't put up with that level of security.
Heck, look at how much people complained about the UAC prompts. Imagine how annoyed they'd be if MSFT forced them to log into another account to change their system configuration.
Yeah, okay Larry. UAC is marketed as a security feature on various Microsoft sites. The fact that no one really knows what UAC is anymore is your problem, not ours. There's a lack of consistency across the board and you guys should be embarassed.