Not strictly true, Burngate.
Computer output devices used both Cathode-Ray Tube (CRT) devices and hard-copy devices over the years.
In 1949, the first (British) stored-program computer, EDSAC, used a CRT, derived from radar displays, for its binary output. (Input was by means of a rotating telephone dial!) See http://www.dcs.warwick.ac.uk/~edsac/
, where you can download an EDSAC simulator for your PC or Linux machine. (I haven't tried it on my RPi yet.)
Then, for high-volume printed ouput, the industry moved towards line printers. Those machines were built around a horizontal drum which contained lines of 120 or more characters arranged as:
Opposite each letter position was a hammer and between the row of hammers and the drum were the paper and an ink ribbon.
The drum rotated at high speed and as each letter for the required output line came under the row of hammers, appropriate hammers were fired at the drum.
So the output line:
THE QUICK BROWN FOX" (only capitals were available) would be printed as:
O O then,
F ... and so on.
(Hope word-wrapping doesn't mess the foregoing up!)
The lines of letters were arranged in sequence according to the frequency of letter usage in the English language. Other languages had different sequences.
See the Wikipedia entry at http://en.wikipedia.org/wiki/Line_printer
for pictures and more details.
Other variants of line printers included chain and band printers.
For low-volume output, CRTs (or VDUs) based on TV technology became popular again. The first one I commisioned was a Cossor shadow-mask device, so called because a stencil-like mask of characters (upper-case only, I think) was interposed between the cathode ray and the screen. By pointing the cathode-ray beam appropriately, letters and numbers could be painted on the screen. Not very flexible, though.
Both line printers and CRTs, of course, are output-only devices. To allow operator input, a keyboard of some form had to be provided. So a logical step was to use teletype techology, which was adapted from typewriter technology, to combine operator input and output into a single, handy device.
Early devices used the first typewriter technology of flying typebars, which were prone to jamming. (Did you know that the QWERTY keyboard that we all have even now was designed to be inefficient, to prevent fast typists jamming the machine?) At least, we now had lower-case letters!
However, typewriter and teletype technology moved on to having a drum of letters, then a flat matrix of letter pins, which moved up and sideways over the printed sheet to be hit by a hammer device. This is the techology, which culminated in the IBM Selectric golfball typewriter, that I think you are referring to.
Nowadays, of course, output is enabled by high-graphic CRT or LED displays (and inkjet and laser printers), with separate input devices. Has much changed from the days of EDSAC?
I hope that adds to the discussion. If I've missed any old technologies, let me know.
IT Background: Honeywell H2000 ... CA Naked Mini ... Sinclair QL ... WinTel ... Linux ... Raspberry Pi.