I agree with the main point, that mathematically they should be going for things that take advantage of the UA directly, but aligning advantages of the same type is still valuable as any choices down the line become stacked. If you have a great artist that you can turn into a golden age or a great work, if you have chichen itza & freedom & persian UA taking the golden age becomes very lucrative. Or the games project 500 happy. Or Taj Mahal
Yeah, you're absolutely right (I tried to allude to that with my analogy to Babylon and the Porcelain Tower, but you put it better). The thing is that, especially on the higher difficulty levels, as Brazil, it's probably worthwhile to beeline Civil Service and do whatever you can to get Chichen Itza; as Persia, it's just not important enough to justify that. You can always invade the guy who does build it!