Sure, and that works up to a point, but ultimately, the AI needs more information to make better choices and more information requires more processing power. There's no way around that.
Yes and no. Like this gets ridiculously complex, fast, and I haven't studied AI formally in some time (my development experience took me on a wildly different career path - I build features and services for educational software), but it very much depends on what the data is, how it is stored, where it is processed, and so on.
For example, take pathfinding. Pathfinding is basically "AI" in its purest terms (most modern pathfinding uses some variant of A*, but I'm sure there are isolated use cases for depth-first and other algorithms that give a better return in very specific contexts). The "information" needed for effective pathfinding is basically map vision. It has less to do with what is on the tiles, vs. how many tiles there are, because all tiles need to be scanned to see if there's a viable movement path. Ten tiles with one unit on each is the same as ten tiles with a theoretical hundred units on each. There's more data, but most of that data is irrelevant to the algorithm's decision.
So let's take a combat AI. The principle of "you need more information" is true, but in video game terms there are distinct differences in processing more data on an individual entity, and multiples of that individual entity. In Java terms (sorry, that's where I learned to program), adding ten attributes to a class is probably more performant / less impactful on performance than having two instances of that class at runtime. Ultimately, "it depends", and I can't begin to guess at the performance constraints that a complex and mature game engine like Civ's has to deal with (and / or what Firaxis are able to iterate on, replace each generation, etc). But "more information requires more processing power" is a truism that only works superficially, because technically you're correct. But in real terms, one addition might require 0.0001% more processing power, and another might require 0.5%. You can have many more of the former additions for the price of one of the latter, right?
Again, bull. More information leads to better decisions and more information requires more computing resources. Do you want to know why the AI isn't "better" in current titles? That's why.
Generally-speaking, the AI isn't better in a lot of games because it's a hard problem to solve, and the attitude to games development as a business doesn't incentivise investing more than the required amount to get it functional. AI in strategy games is a problem across the space, from 4X to grand strategy to RTS and beyond. Some games do it better, some games do it worse.
But if you look at the fixes that modders were able to apply during the course of Civ VI's lifetime (e.g. without the mythical DLL access, so purely within the scope of data provided by the game accessible to anyone with the official tools) before the devs were able to (and this applies to general bugs, not just AI issues), it becomes clear that assigned
resource is more of a factor than the potential of the platform's hardware that the game runs from.