Yeah, you and me both. Morrowind was really the start of the dynasty of modern Bethesda games, and their influence on the rest of the games industry with every release. Although TES existed in 1994, I dont really consider Arena to be anything like Morrowind, and although I haven't played Daggerfall I have a feeling ill find it lacking likewise in open world roleplaying potential.
That particular breed of space sim have been around for a long time though, since the 80s with Elite. The first space sim that I got really into was Freelancer, when I was a kid around 2003. You should also give that a play if you're looking for some open-world goodies. Its actually somewhat closer to a Bethesda game than the other two I listed, Freelancer is quite story focused, but during the plot you're given a quite a bit of wriggle room. The game doesn't end when the plot ends, you've got the rest of the universe to explore, and that when it kicks into full open world drive and you can do whatever you want. I dont think it would ever give you the hundreds to thousands of hours that Bethesda's masterpieces do, but its still a lot of fun if you're looking for a break.
Just a small nitpick here, but I think you've got your history wrong. COD1 was a PC only title way back in the early 2000s, and it really blew everyones mind back then. COD2 was a Xbox 360 launch title, although it was on PC aswell. COD3 was console only, but im pretty sure its multi-platform on those, and then COD4 came out for everything except the Wii.
As much as I really dislike newer COD, those first 3ish installments were really nice as a sort of 5-10 hours of shootmans fun. Again, nowhere near the same caliber as what we usually play, but it did break some very new ground back then.