I've been brewing for 15 years, so I mostly missed the bad days, as well as the mediocrity of the 90s brewpub movement. What I did drink then I couldn't tell was bad (or at least, any worse than Rolling Rock).
I do, however, have a book from my grandfather who was a very early Homebrewer. It's called "Home Brewing Without Failures", by HE Bravery, and it might be one of the worst things I've ever read. It was published in England in the 50s and republished here sometime in the late 60s, and has recipes with 100% crystal malt, overnight mashes, and other atrocities. I give him credit though for making beer in the 70s, as well as ordering grape root stock for homemade wine from New York back when it was considered a major winemaking region for the east coast.