Yeah but airlines don't know if you are flying with your mistress or your sister.

And credit reporting agencies don't have your IMs, or know that you mailed hotchick2012 43 times this week, and started doing so 5 months before you changed your profile status from its complicated to single.

Walmart doesn't have facial recognition cameras up in every store tracking you. So you can just go to another store and make your purchase, keeping all your patterns intact.

The issue with putting 2 and 2 together is an issue which reared its head only post the camibrian era like IT explosion.

The old big box retailers do not have the same level of connection to your thoughts and personal information the same way online companies do.

They could do that, but only after they drastically upgraded themselves to specifically start profiling and tracking each individual - essentially by becoming more like facebook/social networks.

Your argument soars and falls depending on how connected to your personal information/social network a retailer is.

The only likely exception to that is your pharmacist - their domain of knowledge gave them pretty deep insights into your life even before the advent of the net.