True open world allows to ignore missions and do your own exploration.
That might be how someone sees something that is linear or non-linear, but by default that isn't the term of open world.
It can be part of it, but its not some requirement and even the games many mentioned have options for all the things you just said.
You can ignore missions and quest in Spiderman, Horizon, Ghost Of Tsushima, God Of War 2018 and Ragnarok, same with Days Gone and many more, you can freely explore those worlds too...I don't know what to tell you, but those elements are not absent from those titles to pretend as if that was what you were talking about or something lol
"Even the rpg elements have been dumbed down as time went on."
Sure, that still has nothing to do with the term open world.
The games people have just listed literally have all the things that fit that term so......yea.