"We could be looking at a dangerous, privacy-invasive service and still have some trust because it's wrapped in lickable buttons and subtle gradients. "
Since when did the design of a product ever say anything about privacy-invasiveness? If anything the correlation seems backwards to what he's suggesting; many of the companies who "got" good design early on and are best known for good design are the ones I trust the least when it comes to privacy.
It's the same reason old banks look so nice (and expensive): someone who has obviously invested in appearance is sending signals that they're sticking around for a while, which implies they won't take your money and run. I think it was Tim Hartford who wrote about this in a book, but I can't find the reference now.
Since when did the design of a product ever say anything about privacy-invasiveness? If anything the correlation seems backwards to what he's suggesting; many of the companies who "got" good design early on and are best known for good design are the ones I trust the least when it comes to privacy.