The earliest computers took up entire rooms, but in the 1970s, small microprocessors, like the MOS 6502 microprocessor by MOS Technology, became available, allowing computers to be manufactured for home use. The most popular home computer during much of the '80s was the Commodore 64, which sold for $595 upon initial release.
Some models, such as the Apple II and Tandy TRS-80, came with monitors, but most, including the Ataris, the Sinclairs and the Commodore 64s, were keyboards that attached directly to your television. Many had no internal storage, necessitating the purchase of external devices such as tape and floppy disk drives to allow you to save your work magnetically. Their RAM ranged from 1 KB to 64 KB (a scant amount by modern standards), but the devices allowed us to create and play graphical games, perform word processing and do complex calculations via computer, things the average person hadn't been able to do before.
The computers that doubled as gaming consoles, such as the Ataris and Commodores, allowed you to insert game cartridges. But they also allowed users to write programs in various flavors of BASIC (a more user-friendly programming language than most others of the era). At a time when there was little software available for purchase, you could buy books and magazines containing prewritten programs to retype and run on your home system, or you could write your own. Whichever you chose, you were learning at least a little programming along the way.
The devices allowed you to work on a command line, boot into programming environments and otherwise become familiar with the back-end operating system out of necessity. The Commodore 64 had a rudimentary graphical menu system, the predecessor to modern graphical user interfaces (GUIs), but you still had to know more about the computer than you do nowadays. Several of these systems attracted kids and adults alike via the games, but they also encouraged learning to program in order to get the most out of the machines.
As computers became increasingly complex over the '90s, and gobs of prewritten software became available, computers morphed into fully functional and indecipherable black boxes. Most modern GUIs hide the back-end processes of the operating system. Games and other software are impenetrable, and you have to install special software to write and compile programs. Unless you work in or study IT, you never have to go to the command line or write your own software.
This evolution has helped bring us to the current crisis. There's less need for people to tinker with the inner workings of computers, and the focus has shifted to more mundane uses (like using office software, sending e-mail and surfing the Internet). Since PCs have become as central as television to many of our daily lives, many parents aren't likely to let their kids needlessly tamper with their expensive family computers. The Raspberry Pi could bring us out of this predicament by providing a programmable device that anyone can play with, including children.