When in gameplay after I die, how do I reload the last Q save without quitting the game and rebooting? It's because all my food, money and half my health is removed after resurrection and I need my rupees.. sorry, gold coins, to buy Sorsarn Cornish pasties and bribe the kings to heal me.

My weapons and armour get looted too and it's shameful to wander around labyrinths with my greatsword unsheathed and my blaster rifle missing.

i'm afraid to say closing the game and restarting it, is how you'd reload from a save. sorry man
the game was made in the era of when your done playing a game you shut off the PC

I'd heard a rumour about that but this confirms it. That's kind of weird as even Doom and Wolfenstein quit back to the DOS command line when quitting the game as did the first Tomb Raider even when on the early Windows.

Later Ultimas like Underworld also let you quit. Did ejecting the disk quit the game or did it just glitch the computer?

The games you mention are more recent. Doom and other games of that era ran under DOS and therefore there was something for the game to quit to. The early Ultima games were released on systems that did not have an operating system; therefore, one couldn't just "quit back to dos"; there's no DOS to quit back to!

Ejecting the disk would, I believe, typically work something like this:
*: With no disk in the drive, the game would play fine until it has to load from disk, at which point the game will ask you to insert the disk into the drive.
*: With the wrong disk in the drive, some games will catch that and ask you to insert the correct disk. Other games, however, will fail to check that and result in the game loading data from the wrong disk. This can result in the overworld being messed up (possibly being exploitable to reach places you shouldn't be able to), and if it tries to execute what it thought was code (but really isn't), the computer could crash. (I believe that, on at least one model of the Apple II, it was possible for code to actually melt down the monitor.)
*: Trying to remove the disk while it is being accessed (and there is a light on the disk drive to indicate this) could actually physically damage the disk or the disk drive and is therefore not advised. (Once the hard 3.5 inch floppies started to appear, you started to see drives with an electronic eject button that would prevent this from happening, just like in CD-ROM drives.)

So even though Ultima 1 on GOG is the dos version on Windows, it functioned like the original Apple II version that didn't have an actual OS and just had a basic command line, meaning that quitting literally wasn't an option.

Well the DOS version on a DOS emulator, yes. Ultima VI is the first to give you a proper quit option and VII is the first to have an in game load option. DOS had you just hit the power button when you were done, that did not change until Windows came around.

Ultima V (DOS version) also had a proper quit option; it was just not documented. (I believe it's Ctrl-Q)

Even on NEXTStep (possibly Xerox?) GUI OS that was used to create Doom and that Microsoft and Apple based Windows and Mac upon?

http://www.folklore.org/StoryView.py?story=A_Rich_Neighbor_Named_Xerox.txt

If Ultima V does have one, it isn't ctrl-q. I happen to be replaying that and just tested it. Well I have no idea about that. My early OS experience was a little pure DOS and then Windows starting with 3.1. A little Apple II through School too, though we never turned those on or off. And then my dad's first computer had some odd OS that I never knew what was, except that it was apparently not a pre-3.1 version of windows. My main point was DOS had no reason to care if you just turned the computer off.

Edit: Well what do you know. Ultima V does have an quit option after all, it was ctrl-e though.

Another poster pretty much answered this, but I just wanted in on the nostalgia of gameplay in the late 70's early 80's. I remember playing a football game that was text based and you put your phone on the modem. I was like 11 or something. Blew my mind. But he's right. Your operating system was your head. You had to know basic at the very least to some degree. You wrote command lines: 10: run xxx, 20: col 2345, 30: go to 10, that's not the right code, but that is an example of how you could create a simple loop that would put a color on your screen from top left down to bottom right. You could tweak around and make a kaleidoscope, or eyeballs, or even a rough sketch of a stickman. Like what "Draw" is today, but using basic.
"Windows" were invented to help hvy user folks from having to keep typing the same command line over and over to do the same task over and over, like accessing a certain file. I couldn't keep up with all the changes and b4 the 1990's came around, Windows and Apple OS were pretty much all that was left. I hate Win 10, it's spyware forceware adware/OS and they have put shell after shell and layer after layer on top and fused within their OS that I no longer feel like a computer person, just a person using a product. That's on me. But at one time windows was pretty damn cool and sexy.
Anyways, gaming back then as a tweener was so damn cool in 1980. Anything on a computer was so new and different, and there were so many computer brands to choose from. I think it was from like '79-'83 or so when most pc gamers were super nerds or siblings of super nerds, or friends with super nerds who could show you how to use a computer to play a game.

There was also, of course Unix and other mainframe operating systems. There you may have had to type in commands, but other than that, you still had features that are recognizable in modern OSes, like memory protection. (Remember being told to reboot the computer when your game crashed? That's the result of a lack of memory protection.)

Unix does live on these days; even considering only common desktop operating systems, we can say that Mac OS X (and hence iOS) and Linux (and hence Android) are what Unix has evolved into, with GNU/Linux being the one that feels closest to classic Unix. (Mac OS X is only Unix-like at the lowest levels; the upper graphical layers are Apples's own thing (though I believe they evolved from NeXTSTEP), while iOS and Android are quite different (they have different security models, for example).)

In any case, Unix did bring with it some games, including, rather notably Rogue, You can see some influence from that game here, like how enemies move only when you do, for example. You may have heard the term roguelike; Rogue is the game that named the genre. Even now, there are lots of Linux roguelikes out there, including the likes of nethack and crawl, and of course some modern commercial indie roguelikes have Linux versions.