Original UO was NOT server-wide pvp. It was never intended to be that way nor was it ever that way.
It WAS, indeed, Server Wide PvP, with only towns and guard zones being somewhat "safe". Unless of course someone, say, poisons their own packy with empty bags on it, and lets it die at the bank.
Then, a new player could open the corpse, not knowing initially, very likely, that they would "Flag" grey, and could be killed where they stood...
It was, indeed, Server Wide PvP. Server Wide Non-consensual PvP, at that.
What it was, however, was an open world where you could do anything.
Yup...anything...I was there...have played since Aug of '97...PKing and Thieving were rampant.
If that included attacking other players, then I guess that was your play style. I played for years before trammel came out, and I can't remember ever getting pk'd.
Being that Trammel came out in about May 2000, and UO came out in late '97, "Years" might be a stretch. If you "Never" got PKed...good for you. That was NOT the case for a crap-ton of OTHER players, however...a Crap-Ton.
The vast majority of the population base was there just to play the game and have fun. It seems to me that most people who never played before trammel think that it was a vast slaughterhouse full of warring characters who never did anything fun but look over their shoulder.
I played before Trammel. I remember it very, very well. My memory is not jaded by the PKs, but they certainly are a large part of my gaming experience prior to Trammel. The wife and I both quit about 6 months prior to Trammel coming out, but luckily kept our account. We had quit playing specifically because of leg-humping thieves, and the PKs. We were certainly NOT alone in our feelings about these game experiences, either...not by a long shot. Even Anthony Castoro, that Producer that did such a very poor job of implementing Trammel ( "It will NOT be a mirror of Felucca" or whatever he said that was patently NOT true...but a different discussion, for sure) said that a small group of highly skilled players were griefing the living bejeezis out of the general population (which does back up your point that "Most People Were There to Have Fun")...it is just that the small groups of highly skilled players made life miserable for the rest of us (I am not, nor have I ever been good at PvP much...don't care for it personally...particularly Non-Consensual PvP, as it was prior to Trammel...and please spare me the "When you logged in, you were consenting to being attacked!!"...not even close.)
You have to remember back then armor ratings made sense, there was no insurance, few blessed items, and items were just not valued like they are today. When going hunting I'd go out and buy a brand new set of armor called a Archer or Dex suit. (Chain tunic and legs, ring gloves, plate arms, plate gorget, and close helm) This ran about 1200 gold back then. Purchase another 2 GM made krysses and that puts you out another 500 gold each. If you died and lost all your belongings, you were out roughly 2000 gold. But you know what, the pk's had the same armor and weapon choices, so pvp back then was WAY, WAY more about skill than what kind of suit you were wearing. It is not the case anymore with outlandish multi-billion gold suits.
Do you remember how much a "Supremely Accurate Kryss of <Insert Highest Destruction Mode Here>" cost back then? How about a whole set of "Invulnerable <Insert the Rest of the Best Armor Qualities Here> Plate Armor?
I don't remember exactly how much these types of items cost, but it was sure a hell of a lot more than 2200 GP. And as I recall, I would get attacked in Shame by 3-5 Reds sometimes, all kitted out and rolling together in their kick ass suits, which WERE a lot better than a Dex or Archer suit...by a very, very long shot, for sure. They HAD the same choices as I did, they were just able to KEEP their stuff when they ganked a single blue in a Dex suit...because their crap was a lot better, and there were more of them. Plus I sucked at PvP, and was there to fight monsters. In addition, it always sucked real bad to be fighting a dragon, and be half dead, and then have the three reds roll up...some fun that must have been for them! It happened a lot, too. Not a little bit...it happened a lot.
In regards to the crime system, you could become flagged gray from being caught while stealing, attacking other players, healing criminals, healing reds, poisoning blues with poisoned food or trapped boxes, etc. While gray you could be attacked by anyone.
Yup, as stated above, the Blue Noto PKs were very good at getting innocents to flag so they would take no count, but it happened as often as the Notos were able to pull it off. Very lame...Hella Lame.
In regards to the bounty hunters, yes, there were many players who "tried" to claim bounties. If you successfully killed a murderer or even a blue character, you used to be able to chop up their body and take their head to a guard. The guard would then give the player the bounty on that character, if any. The bounties were posted locally on bulletin boards in each town.
The Bounty system was a major scam. Run your Bounty WAY up...then have a guildy or someone you know take you out, and collect the money contributed by the people that were killed by the Bounty Character. Brilliant. Lame, indeed...but a great way to make some serious gold.
So...to rebut your recollections of "The way it was" for you isn't possible, as you could be dead on in that you never, ever, ever got PKed...or at least "Can't remember".
However, you can be 100% certain that if what you say is true, you were in an extremely small group of players that did not have that experience...many did...at least enough did to force such a huge change on the game due to the exodus of players around Y2K to Everquest...a game that didn't allow the "Server Wide PvP'" that was UO at the time.
After all...if UO was so swimmingly successful, and DIDN'T have the plague of Server Wide PvP...why in the world would anyone in their right minds change a thing for such a perfect game? Right?