They could easily introduce AI based on machine learning and after a week of having the data from a couple of million game hours to train on, every player would be obliterated despite setting hard limits to make it more human-like (reaction time, aiming etc). I doubt that most of the players want to feel like a noob on some kind of e-sports arena final. Even if you're in the top 10 players on this planet, your skills and strategy will be eventually matched and exceeded by the AI and your rage quit inevitable. Having good AI isn't a problem. Having AI dumb enough to be defeatable and believable is the challenge.

Games with great AI: Unreal & Unreal Tournament, F.E.A.R., Perfect Dark. Those games are 15-25 years old now and AI has only gone downhill since.

It's not hard to program AI at all, devs just make different choices, probably because no one ever talks about AI so they don't think it's a big selling point.

A loong time ago, I was playing Syphon Filter on the PS1 and I was just mowing through the enemies. And out of nowhere, this one random bad guy started behaving like a real person. Like he really wanted to live. He wasn't a boss or anything, just one of the nameless cannon fodder. I can't even remember if I killed him or if he killed me but it was such an awesome moment that I never forgot that it happened.

Every generation, I look forward to moments like that but I can't think of many examples. Maybe I need to start playing on hard mode. I think companies depend on online mode for that experience but I'm not really an online player anymore.

Enemy AI is pretty good in Age of Empires 2 Definitive Edition.

Easy- Easily beaten by 90%+
Normal- Easy for most players
Hard- Is hard for the average player
Extreme- Majority of players can't beat, only top 50% ranked players have a chance.

From what I remember GoT only have the lined up 1 on 1 for duels, and well code of honor and all that wouldn't make sense to make it different.

They are still 'clever' moments. Bosses in Halo Infinite also sometimes run behind cover to recharge their shield. That already feels annoying, got to take that shield down again. To limit the annoyance, they only do so sporadically when fully depleted, while also routinely standing still absorbing hits. If they would run and hide all the time when they lose half shield, coming out guerilla style to deliver a few shots and fade away again, you would get frustrated pretty fast. Just like if all of those up there decided to teleport rush you.

Now and then the AI is allowed to show you that they can easily beat you, but then get chastised again to be the dumb bullet sponge not to hurt the player's ego too much. If the AI was allowed to coordinate attacks, like one stuns you or your vehicle with electrical damage while others concentrate their fire on your spot or where you will be, you wouldn't stand a chance. Duo bosses are also not allowed to position themselves in such a way that they keep you in between them. They always have to be sort of together on one side, or one has to remain stationary until you're done with the other one.

In Halo Infinite you can see what damage good AI with powerful weapons can do. Load up a Razorback with 5 marines with op weapons, rocket launchers or lasers, and you can simply drive through anything while the marines take everything down in your path. Legendary becomes piss easy that way.

The best AI I remember is all the way back to bots in Unreal Tournament. They were programmed to play like actual players do. Lot of strafing, jumping, dodging, getting behind you, using the environment. They were quite good to prepare you for online play. Yet for single player, imagine a squad of bunny hopping grunts dancing all around you, shooting and throwing grenades at where they think you will be when the projectiles hit. They're not even allowed to run at you in a zig zag pattern, straight in to make easy targets.

It seem like the consensus is that gamers like stupid AI. That makes sense. I'd still think that there's room in the market for at least some games with smarter enemies. But, maybe not.

Hasn't been any good since FEAR, maybe the casuals thought it was too hard.

Oh, just a box...

Smarter they sure can be, but you asked more realistic.