You're response sounds more like a marketing brochure to me. While I love tech and am in the tech world, the fact is, mine and everyone's private info is out there for anyone to buy and many companies to sell. Sure, we can make tools (some day) to put the equation in our favor, but this is not that day. Simply saying we can use Tor/private browsing/avoid social media is only part of it. Actually buying things not in cash leaves a trail and that info is sold to whomever pays.
Regardless if you could easily find out in the 1700's if someone was pregnant, the article was not a commentary on the past. It was about opting out in the present, which is pretty much impossible if you use any kind of connected technology in your daily life. Be it your atm/credit card, phone, internet connection - they all leave trails.
Sure, in the 1700's a butcher would see your face and maybe remember it. Maybe retain enough info to track you down if need be. But now, it's more than absolute. The more everything becomes digitized, the less anyone can be anonymous. You'd have to really be into the spy mindset to cover your tracks and do the things that would need to be done to get false ids, etc. And I don't know how much that would even help as machine learning and face recognition (coupled with ccd's everywhere) get better and could probably link up those fake ids.
Honestly, I don't care much because I'm not a very important or interesting person. So in a sense that way, I have some anonymity. And I love tech (still). Interesting experiment from the author, but we've already crossed the privacy line and there's no going back or opting out.