Chicken it'sya is an AI wonder. nuff said.
Oh, I don't know. It's pretty fun to build it in cities bordering other human players in "coop" multiplayer

. Sistine is obviously the best for that though.
For example, I like to have them join my cities as super-specialists.
A settled specialists will never, ever catch even a mid-game golden age...even more so if you aren't SPI and therefore use the GA to avoid multi-turn anarchy.
I find that stacking 4-5 Great Generals on a city with West Point and the Red Cross can make super-soldiers that can break even the toughest of defenses, or defend cities against even the largest of armies, so I don't like to use them for Golden Ages.
We're not playing civ V. You can't use great generals for golden ages! Also, west point and especially red cross are a waste of time. Medic promos don't stack so 1 super medic is good enough, while the massive

investment on west point for a few extra xp is a joke in an era where you can already mow everything down with siege + anything covering it, or draft rifles, or nukes.
Golden Ages give you short term (or turn, hur hur hur) gains without long term rewards, having your Great Person join a city or produce their special building might seem poor in the short term, but in the long term it can really boost your game, especially with the right civics.
Let's say a golden age adds 100-150

and 50

(very small amount for the mid-late game when you'd consider burning one). Between the bonus

and

, you're likely looking at an instant 800-1200

and 400

. A settled great scientist in a 200% research city under representation would take, at the fastest, 45 turns to match that with the 800, and 60 turns to match it if you're closer to 1200.
But it doesn't stop there. If the GA saves you any anarchy, then it would take your settled GS in an oxford supercapitol with representation 80+ turns to catch a comparatively pathetic golden age.
Settling in general stops being a valid consideration after the very early game. Just raw

from bulbing would take around 50-75 turns for a settled rep scientist in an oxford city to catch.
But it gets worse for your settling theory, because so far we haven't even considered present value, or what the

earlier means to an empire. Bulbing and GA both unlock benfits sooner, such as that oxford that is often not even worth building sooner, and gets you to techs that improve your tile yields and civics that raise your output even more sooner.
After you're in the early-mid ADs, a settled great person is unlikely to beat out alternatives even if the game continues on to very late techs such as space. It's not good play to settle other than very early, and it's strictly awful play to settle in the renaissance instead of founding corporations and using them for golden ages.
Hey, I have seen Snaaty (that guy for your information is a godly player; don't dare gainsays him) selfteching DR...YES Divine Right
The hidden benefit to getting DR first is your ability to trade **** the AI *after* you build the wonders you care about, since they often leave it alone until very late. He got more from it than just the wonder most likely.
I think we have a disconnect here between people who are taking this as "worst wonder strategically, when your goal is to have the highest-scoring/fastest-finishing/HOF-type victory", and those who are taking this as "worst wonder for my playstyle".
Space elevator is so bad that it does nothing in 99.9% of games for any playstyle, unless one's playstyle is to deliberately make poor choices. Pursuing it is an active detriment to a space race finish date.