Setting aside that there was more about thief than "Stealth", you know Looking Glass made... other games, right?
I know. I'm mostly winding up 90s PC game fanboys.
Looking Glass are to 90s PC game nerds what The Beetles are to boomer music fans. People talk about how amazing The Beetles were, how every song is a classic, but outside a few big hits, they can't name or hum anything else. Looking Glass are kind of the same. It's Thief and System Shock, no word on the many flight sims they put out.
As a general rule, I consider someone a fanboy when either
- Their love of a thing ignores reality.
- Their love of a thing is expressed more as a hatred for a perceived rival.
90s PC game fanboys, especially Looking Glass fans, do both. They ignore reality when their rose tinted nostalgia goggles have them overlooking or handwaving massive design flaws. I mentioned guards killing themselves in Thief, but things like guns being made of cardboard in System Shock 2 spring to mind as obvious flaws I'm supposed to ignore.
They are also guilty of point 2 by shitting on Dishonoured (and a lesser extent MGS) whenever they get brought up. I have no real love for Kojima, but seeing him credited with anything sends his haters into a rage.
I mean, as a specific example this is a very poor one - Shinji Mikami himself admits that Alone in the Dark was a major influence on the design of Resident Evil. So... Yeah, it kind of did.
You're missing the point.
A while ago I was going through the works of Shirow (the guy that made Ghost in the Shell) and I came across an OVA called Black Magic M-66. It was a blatant rip off of The Terminator, so imagine my surprise when I learned it pre-dated The Terminator by a year. Does that completely invalidate The Terminator? Not really. Would there have been a bunch of straight to video movies about killer robots if The Terminator never existed? I doubt it.
Shogo did the whole "immersive story based FPS" thing before Half-Life, but Shogo didn't change FPS games forever in part because Shogo is not very good.
There are lots of times we can point to the "first" to do something, but the fact is that some did it better, or were more popular. Some people seem to get fixated on whichever one they decided was "first", ignore examples before, and dismiss examples after.