I find many games where the AI is just too dumb for it to be fun. Overall, it's not smart, and it works for a casual player, but for hardcore games, it's just too dumb.
I agree. The thing is, I'm not a 19 year old student any more. I don't want to be a hardcore gamer today. I don't have time to learn FPS maps well enough to navigate them with my eyes closed and still lob a grenade/rocket everywhere the respawn/power-up/camper is likely to be. I can't sustain multiple keyboard/mouse actions per second over a half-hour RTS game. I have no interest in playing against an arena where 1 in 3 opponents is a bot that never misses, nor installing so much mandatory crapware to prevent this on my computer that something outside the game breaks.
For symmetric competitive games, things like arena-based FPS or RTS genres, the "single player" has been going up against bots on PCs since at least the days of Quake 3 Arena, which was around the turn of the century. The big RTSes of that era often had some sort of contrived plot and a series of preplanned missions, but the replay value as a single player was all in open gaming against bots. In each case, playing against real people on-line was always the natural successor; this is not a new thing.
But there used to be asymmetric games as well, where the storyline and gameworld made for a much more compelling experience that could feel more like being in an interactive movie than playing round 17 of laser tag. Classics like the Baldur's Gate series or the original Deus Ex come immediately to mind. They avoided the boredom of facing what you called "pattern AIs" by having actual progression through the game, so the situations and capabilities you'd face would be changing. You can't really do this in a multiplayer gameworld when everyone wants to start with everything and the game only ships with 2 maps. (*97 more maps are available as DLC. Payment required.)
AIs have improved since those days anyway, but the biggest problem for single-player gaming is that the industry has so completely given up on games that require actual progression and development that fighting AIs on the same handful of maps is all the replay value they've got.