Yeah, that’s almost certainly true. We’ve said here and I’ve heard it elsewhere but I don’t think Firaxis has any desire/concern to make the AI “good” or engaging. It just needs to be present for most of the gamers that play Civ, I guess.
I always have so much fun in the first 2-3 hours of a new game, which is why it’s such a shame about the late (or even mid) game. I probably won’t bother finishing my Netherlands game either, between quitting in irritation/frustration last night and now Stellaris out in an hour. A shame, but like I said I don’t actually regret the $25 investment since I got about 8 hours of decent fun out of it, and hey, maybe someday they will make the AI a little more engaging and I can enjoy a full game? Anything is possible*.
*Likely with mods.