It wouldn't surprise me if physical advertising, as mentioned in the post, makes a comeback. Especially coupled with magazines etc apparently making a comeback too.

Also, a lot of ads now have QR codes so you can tell which physical ads are driving versus traffic versus those that aren't.

e.g. the "half of my advertising is a waste but I don't know which half" is not true anymore if you are using specific QR codes per location/advertisement.