Electronics jibblers will remember databooks. Back before the mid-2000s or so, if you wanted to know the specs of a component you had to look it up in a book, and every well-equipped electronics lab would have shelves of these telephone-directory-sized publications, and hopefully a photocopier somewhere nearby. These days you can just type the part number into google and get the manufacturer's datasheet PDF in the first few results.
You can accurately date the rot setting in by when the Maplin catalogue abandoned the middle chapters of pinouts of all the common 4000-series logic ICs, op-amps, power regulators and such that hobbyists were likely to need. I think they may have offered them on CD-ROM for a while, but I had access to university facilities by that point.
I'm not sure how accurate my perception is, but it seemed that hobby electronics almost died out in the 1990s and 2000s, as consumer goods became increasingly difficult to fettle, and the suppliers of parts became more and more industry-oriented. Fortunately, the Maker movement seems to have re-kindled interest, albeit where the electronics aspect is often an incidental part of a larger project. Today's tinkerers are more likely to learn electronics as they work out how to interface some sensor or actuator to their Arduino or Raspberry Pi project than by mucking around with jellybean transistor circuits, radios and 555 timers. And in today's world, that's a lot more useful.