Was a mouse even an option in the late 70s? I mean, I know they had been invented and used with a few computers, but I was always under the impression they didn’t take off until the mid-80s.
The Mac was first introduced in Jan. 1984 - first graphical interface PC. Copied from a Xerox Parc research computer of a few years earlier.
Again, free-form graphical displays required even more RAM than text displays. For example, a 640x480 colour VGA display, that’s about 32,000 pixels. At 4 bits, half a byte, per pixel -allowing 16 colours - that’s still about 16K, more than most home computers had for working RAM in 1977. (Commodore 64’s were named to boast about the 64K chips they used for RAM, a huge amount for the time in 1981)
So the tech for graphics was far behind the tech for type. IIRC the Apple II was a 320x200 graphic screen, forget how many colours (4?) and the TRS-80 was 640x400 monochrome. Commodore Pet did not have graphics, it had an extensive variety of graphic characters; or you could toggle from graphical to mixed upper-lower case.
Right you are wolfpup. Maybe I should have said the VAX changed everything for me. Saw a PDP-1 at the Computer History Museum in Mountain View, CA. Too much.
My dad had a PDP-6 in his lab back in the early 70’s. I remember reading the manual and entering a simple loop program of about 10 instructions - using the front switches, since I had no access to teletype paper tape punch. he had an old surplus teletype as the input output device for some canned programs.
TVs were used for the first personal computers because they were a great deal cheaper than terminal monitors.
To connect them these computers were designed with a modulator to create a TV signal. However TVs were designed to a lower specification and often the stability of the display was not good. For moving pictures you don’t notice this, but if you try wordprocessing or programming it is annoying. Also they often could not accommodate a full 80 characters across the screen so often you had to make do with 40.
A monitor, on the other hand had a very nice stable display of 80 characters. I obtained a second-hand monitor from a computer scrap dealer and hooked it up to my kit computer and marvelled at the crisp display and clear, bright phosphor. However being second hand, it did have a screen that had a feint image burnt into the phosphor. Obviously it had been used to display some home menu was left on for a lot of its life, etching in a pattern. You could best see this when it was switched off, a shadow pattern in the grey/green colour of the screen. This burn in effect on CRTs gave rise to a whole genre of mobile ‘screen saver’ programs, which still exist to this day.
Incidentally, the distinction between a monitor and terminal is that a monitor is just a screen. A terminal usually has an integrated keyboard and some elementary cursor handling AND a serial interface by which it talks to the larger computer directly of via modem over a very slow link.
In those days, either you had thousands to spend on a TRS80 or Commodore PET or one of those fancy pants Apple IIs with their color monitor. Or you built your own computer out of a kit and house it in your own woodwork computer case/fish tank or whatever you could find. Printers were also very expensive. The scrap yard provided my first printer, an only Creed teletype. It printed in capitals and made a noise like a machine gun and it was DANGEROUS. It had a big motor and it looked as if it could kill you if your tie got caught in it.
8K Basic in a ROM and a luxurious 8K of RAM and a tape recorder for storage. Somewhat less than many microcontrollers these days. Floppy discs were for expensive business machines and hard disks were a dream. 1970s home computing was very much the realm of the hobbyist with a soldering iron. Similar to todays MAKER community. 
That’s impressive – the PDP-6 was an iconic machine, a powerful 36-bit computer that was the predecessor of the PDP-10, but it was costly and there weren’t very many of them made.
Entering programs via switches (or patching them that way) was something every true hacker (in the positive, MIT sense of the term) had to know. For smaller computers like the PDP-8, it was the only way to start them up. You had to enter a small bootstrap loader through the switches, whose job was to read in a larger and more capable binary loader from paper tape. Then that loader would read in the binary image of whatever program you actually wanted to run. The smaller bootstrap loader was designed to sit in about a dozen locations at the top of memory, so with any luck it was available next time without having to re-enter it, since core memory was non-volatile. But half the time some errant program would have wiped it out, or just needed the space.
BTW, you can still play with this stuff today via the SIMH Project which provides simulators for historic computers, and most OS’s and other software for them have now been released into the public domain.